From 4cc1d40d421c8736f8b21b360b61d6b065158b7a Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Wed, 29 Sep 2021 23:56:16 +0200
Subject: refactor(simulator): Migrate to flow-based simulation

This change renames the `opendc-simulator-resources` module into the
`opendc-simulator-flow` module to indicate that the core simulation
model of OpenDC is based around modelling and simulating flows.

Previously, the distinction between resource consumer and provider, and
input and output caused some confusion. By switching to a flow-based
model, this distinction is now clear (as in, the water flows from source
to consumer/sink).
---
 .../simulator/flow/FlowConsumerContextTest.kt      | 152 +++++++++++++
 .../org/opendc/simulator/flow/FlowForwarderTest.kt | 222 +++++++++++++++++++
 .../org/opendc/simulator/flow/FlowSinkTest.kt      | 240 +++++++++++++++++++++
 .../flow/mux/SimResourceSwitchExclusiveTest.kt     | 157 ++++++++++++++
 .../flow/mux/SimResourceSwitchMaxMinTest.kt        | 147 +++++++++++++
 .../simulator/flow/source/FixedFlowSourceTest.kt   |  57 +++++
 6 files changed, 975 insertions(+)
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
new file mode 100644
index 00000000..061ebea6
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow
+
+import io.mockk.*
+import kotlinx.coroutines.*
+import org.junit.jupiter.api.*
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.internal.FlowConsumerContextImpl
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+
+/**
+ * A test suite for the [FlowConsumerContextImpl] class.
+ */
+class FlowConsumerContextTest {
+    @Test
+    fun testFlushWithoutCommand() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val consumer = object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (now == 0L) {
+                    conn.push(1.0)
+                    1000
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        val logic = object : FlowConsumerLogic {}
+        val context = FlowConsumerContextImpl(engine, consumer, logic)
+
+        engine.scheduleSync(engine.clock.millis(), context)
+    }
+
+    @Test
+    fun testIntermediateFlush() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val consumer = FixedFlowSource(1.0, 1.0)
+
+        val logic = spyk(object : FlowConsumerLogic {})
+        val context = FlowConsumerContextImpl(engine, consumer, logic)
+        context.capacity = 1.0
+
+        context.start()
+        delay(1) // Delay 1 ms to prevent hitting the fast path
+        engine.scheduleSync(engine.clock.millis(), context)
+
+        verify(exactly = 2) { logic.onPush(any(), any(), any(), any()) }
+    }
+
+    @Test
+    fun testDoubleStart() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val consumer = object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (now == 0L) {
+                    conn.push(0.0)
+                    1000
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        val logic = object : FlowConsumerLogic {}
+        val context = FlowConsumerContextImpl(engine, consumer, logic)
+
+        context.start()
+
+        assertThrows<IllegalStateException> {
+            context.start()
+        }
+    }
+
+    @Test
+    fun testIdempotentCapacityChange() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val consumer = spyk(object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (now == 0L) {
+                    conn.push(1.0)
+                    1000
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        })
+
+        val logic = object : FlowConsumerLogic {}
+        val context = FlowConsumerContextImpl(engine, consumer, logic)
+        context.capacity = 4200.0
+        context.start()
+        context.capacity = 4200.0
+
+        verify(exactly = 0) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+    }
+
+    @Test
+    fun testFailureNoInfiniteLoop() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val consumer = spyk(object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+
+            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                if (event == FlowEvent.Exit) throw IllegalStateException("onEvent")
+            }
+
+            override fun onFailure(conn: FlowConnection, cause: Throwable) {
+                throw IllegalStateException("onFailure")
+            }
+        })
+
+        val logic = object : FlowConsumerLogic {}
+
+        val context = FlowConsumerContextImpl(engine, consumer, logic)
+
+        context.start()
+
+        delay(1)
+
+        verify(exactly = 1) { consumer.onFailure(any(), any()) }
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
new file mode 100644
index 00000000..cbc48a4e
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow
+
+import io.mockk.spyk
+import io.mockk.verify
+import kotlinx.coroutines.*
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+
+/**
+ * A test suite for the [FlowForwarder] class.
+ */
+internal class FlowForwarderTest {
+    @Test
+    fun testCancelImmediately() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        forwarder.consume(object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+        })
+
+        forwarder.close()
+        source.cancel()
+    }
+
+    @Test
+    fun testCancel() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        forwarder.consume(object : FlowSource {
+            var isFirst = true
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    10 * 1000
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        })
+
+        forwarder.close()
+        source.cancel()
+    }
+
+    @Test
+    fun testState() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val consumer = object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+        }
+
+        assertFalse(forwarder.isActive)
+
+        forwarder.startConsumer(consumer)
+        assertTrue(forwarder.isActive)
+
+        assertThrows<IllegalStateException> { forwarder.startConsumer(consumer) }
+
+        forwarder.cancel()
+        assertFalse(forwarder.isActive)
+
+        forwarder.close()
+        assertFalse(forwarder.isActive)
+    }
+
+    @Test
+    fun testCancelPendingDelegate() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+
+        val consumer = spyk(object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+        })
+
+        forwarder.startConsumer(consumer)
+        forwarder.cancel()
+
+        verify(exactly = 0) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+    }
+
+    @Test
+    fun testCancelStartedDelegate() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        val consumer = spyk(FixedFlowSource(2000.0, 1.0))
+
+        source.startConsumer(forwarder)
+        yield()
+        forwarder.startConsumer(consumer)
+        yield()
+        forwarder.cancel()
+
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Start) }
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+    }
+
+    @Test
+    fun testCancelPropagation() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        val consumer = spyk(FixedFlowSource(2000.0, 1.0))
+
+        source.startConsumer(forwarder)
+        yield()
+        forwarder.startConsumer(consumer)
+        yield()
+        source.cancel()
+
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Start) }
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+    }
+
+    @Test
+    fun testExitPropagation() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine, isCoupled = true)
+        val source = FlowSink(engine, 2000.0)
+
+        val consumer = object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+        }
+
+        source.startConsumer(forwarder)
+        forwarder.consume(consumer)
+        yield()
+
+        assertFalse(forwarder.isActive)
+    }
+
+    @Test
+    fun testAdjustCapacity() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 1.0)
+
+        val consumer = spyk(FixedFlowSource(2.0, 1.0))
+        source.startConsumer(forwarder)
+
+        coroutineScope {
+            launch { forwarder.consume(consumer) }
+            delay(1000)
+            source.capacity = 0.5
+        }
+
+        assertEquals(3000, clock.millis())
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+    }
+
+    @Test
+    fun testCounters() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 1.0)
+
+        val consumer = FixedFlowSource(2.0, 1.0)
+        source.startConsumer(forwarder)
+
+        forwarder.consume(consumer)
+
+        yield()
+
+        assertEquals(2.0, source.counters.actual)
+        assertEquals(source.counters.actual, forwarder.counters.actual) { "Actual work" }
+        assertEquals(source.counters.demand, forwarder.counters.demand) { "Work demand" }
+        assertEquals(source.counters.overcommit, forwarder.counters.overcommit) { "Overcommitted work" }
+        assertEquals(2000, clock.millis())
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
new file mode 100644
index 00000000..010a985e
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
@@ -0,0 +1,240 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow
+
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.spyk
+import io.mockk.verify
+import kotlinx.coroutines.*
+import org.junit.jupiter.api.*
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.FlowSourceRateAdapter
+
+/**
+ * A test suite for the [FlowSink] class.
+ */
+internal class FlowSinkTest {
+    @Test
+    fun testSpeed() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = FixedFlowSource(4200.0, 1.0)
+
+        val res = mutableListOf<Double>()
+        val adapter = FlowSourceRateAdapter(consumer, res::add)
+
+        provider.consume(adapter)
+
+        assertEquals(listOf(0.0, capacity, 0.0), res) { "Speed is reported correctly" }
+    }
+
+    @Test
+    fun testAdjustCapacity() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val provider = FlowSink(engine, 1.0)
+
+        val consumer = spyk(FixedFlowSource(2.0, 1.0))
+
+        coroutineScope {
+            launch { provider.consume(consumer) }
+            delay(1000)
+            provider.capacity = 0.5
+        }
+        assertEquals(3000, clock.millis())
+        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+    }
+
+    @Test
+    fun testSpeedLimit() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = FixedFlowSource(capacity, 2.0)
+
+        val res = mutableListOf<Double>()
+        val adapter = FlowSourceRateAdapter(consumer, res::add)
+
+        provider.consume(adapter)
+
+        assertEquals(listOf(0.0, capacity, 0.0), res) { "Speed is reported correctly" }
+    }
+
+    /**
+     * Test to see whether no infinite recursion occurs when interrupting during [FlowSource.onStart] or
+     * [FlowSource.onPull].
+     */
+    @Test
+    fun testIntermediateInterrupt() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = object : FlowSource {
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                conn.close()
+                return Long.MAX_VALUE
+            }
+
+            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                conn.pull()
+            }
+        }
+
+        provider.consume(consumer)
+    }
+
+    @Test
+    fun testInterrupt() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+        lateinit var resCtx: FlowConnection
+
+        val consumer = object : FlowSource {
+            var isFirst = true
+
+            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                when (event) {
+                    FlowEvent.Start -> resCtx = conn
+                    else -> {}
+                }
+            }
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    4000
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        launch {
+            yield()
+            resCtx.pull()
+        }
+        provider.consume(consumer)
+
+        assertEquals(0, clock.millis())
+    }
+
+    @Test
+    fun testFailure() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = mockk<FlowSource>(relaxUnitFun = true)
+        every { consumer.onEvent(any(), any(), eq(FlowEvent.Start)) }
+            .throws(IllegalStateException())
+
+        assertThrows<IllegalStateException> {
+            provider.consume(consumer)
+        }
+    }
+
+    @Test
+    fun testExceptionPropagationOnNext() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = object : FlowSource {
+            var isFirst = true
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    1000
+                } else {
+                    throw IllegalStateException()
+                }
+            }
+        }
+
+        assertThrows<IllegalStateException> {
+            provider.consume(consumer)
+        }
+    }
+
+    @Test
+    fun testConcurrentConsumption() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = FixedFlowSource(capacity, 1.0)
+
+        assertThrows<IllegalStateException> {
+            coroutineScope {
+                launch { provider.consume(consumer) }
+                provider.consume(consumer)
+            }
+        }
+    }
+
+    @Test
+    fun testCancelDuringConsumption() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val capacity = 4200.0
+        val provider = FlowSink(engine, capacity)
+
+        val consumer = FixedFlowSource(capacity, 1.0)
+
+        launch { provider.consume(consumer) }
+        delay(500)
+        provider.cancel()
+
+        yield()
+
+        assertEquals(500, clock.millis())
+    }
+
+    @Test
+    fun testInfiniteSleep() {
+        assertThrows<IllegalStateException> {
+            runBlockingSimulation {
+                val engine = FlowEngineImpl(coroutineContext, clock)
+                val capacity = 4200.0
+                val provider = FlowSink(engine, capacity)
+
+                val consumer = object : FlowSource {
+                    override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long = Long.MAX_VALUE
+                }
+
+                provider.consume(consumer)
+            }
+        }
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
new file mode 100644
index 00000000..b503087e
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.mux
+
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertAll
+import org.junit.jupiter.api.assertThrows
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.*
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.FlowSourceRateAdapter
+import org.opendc.simulator.flow.source.TraceFlowSource
+
+/**
+ * Test suite for the [ForwardingFlowMultiplexer] class.
+ */
+internal class SimResourceSwitchExclusiveTest {
+    /**
+     * Test a trace workload.
+     */
+    @Test
+    fun testTrace() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val speed = mutableListOf<Double>()
+
+        val duration = 5 * 60L
+        val workload =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+        val forwarder = FlowForwarder(engine)
+        val adapter = FlowSourceRateAdapter(forwarder, speed::add)
+        source.startConsumer(adapter)
+        switch.addOutput(forwarder)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertAll(
+            { assertEquals(listOf(0.0, 28.0, 3200.0, 0.0, 183.0, 0.0), speed) { "Correct speed" } },
+            { assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" } }
+        )
+    }
+
+    /**
+     * Test runtime workload on hypervisor.
+     */
+    @Test
+    fun testRuntimeWorkload() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = FixedFlowSource(duration * 3.2, 1.0)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertEquals(duration, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test two workloads running sequentially.
+     */
+    @Test
+    fun testTwoWorkloads() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = object : FlowSource {
+            var isFirst = true
+
+            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                when (event) {
+                    FlowEvent.Start -> isFirst = true
+                    else -> {}
+                }
+            }
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    duration
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+        provider.consume(workload)
+        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test concurrent workloads on the machine.
+     */
+    @Test
+    fun testConcurrentWorkloadFails() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        switch.newInput()
+        assertThrows<IllegalStateException> { switch.newInput() }
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt
new file mode 100644
index 00000000..089a8d78
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.mux
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.*
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.FlowSink
+import org.opendc.simulator.flow.consume
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.TraceFlowSource
+
+/**
+ * Test suite for the [FlowMultiplexer] implementations
+ */
+internal class SimResourceSwitchMaxMinTest {
+    @Test
+    fun testSmoke() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+        val switch = MaxMinFlowMultiplexer(scheduler)
+
+        val sources = List(2) { FlowSink(scheduler, 2000.0) }
+        sources.forEach { switch.addOutput(it) }
+
+        val provider = switch.newInput()
+        val consumer = FixedFlowSource(2000.0, 1.0)
+
+        try {
+            provider.consume(consumer)
+            yield()
+        } finally {
+            switch.clear()
+        }
+    }
+
+    /**
+     * Test overcommitting of resources via the hypervisor with a single VM.
+     */
+    @Test
+    fun testOvercommittedSingle() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L
+        val workload =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+
+        val switch = MaxMinFlowMultiplexer(scheduler)
+        val provider = switch.newInput()
+
+        try {
+            switch.addOutput(FlowSink(scheduler, 3200.0))
+            provider.consume(workload)
+            yield()
+        } finally {
+            switch.clear()
+        }
+
+        assertAll(
+            { assertEquals(1113300.0, switch.counters.demand, "Requested work does not match") },
+            { assertEquals(1023300.0, switch.counters.actual, "Actual work does not match") },
+            { assertEquals(90000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(1200000, clock.millis()) }
+        )
+    }
+
+    /**
+     * Test overcommitting of resources via the hypervisor with two VMs.
+     */
+    @Test
+    fun testOvercommittedDual() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L
+        val workloadA =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+        val workloadB =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3100.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 73.0)
+                )
+            )
+
+        val switch = MaxMinFlowMultiplexer(scheduler)
+        val providerA = switch.newInput()
+        val providerB = switch.newInput()
+
+        try {
+            switch.addOutput(FlowSink(scheduler, 3200.0))
+
+            coroutineScope {
+                launch { providerA.consume(workloadA) }
+                providerB.consume(workloadB)
+            }
+
+            yield()
+        } finally {
+            switch.clear()
+        }
+        assertAll(
+            { assertEquals(2073600.0, switch.counters.demand, "Requested work does not match") },
+            { assertEquals(1053600.0, switch.counters.actual, "Granted work does not match") },
+            { assertEquals(1020000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(1200000, clock.millis()) }
+        )
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt
new file mode 100644
index 00000000..8396d346
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.source
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.FlowSink
+import org.opendc.simulator.flow.consume
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+
+/**
+ * A test suite for the [FixedFlowSource] class.
+ */
+internal class FixedFlowSourceTest {
+    @Test
+    fun testSmoke() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+        val provider = FlowSink(scheduler, 1.0)
+
+        val consumer = FixedFlowSource(1.0, 1.0)
+
+        provider.consume(consumer)
+        assertEquals(1000, clock.millis())
+    }
+
+    @Test
+    fun testUtilization() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+        val provider = FlowSink(scheduler, 1.0)
+
+        val consumer = FixedFlowSource(1.0, 0.5)
+
+        provider.consume(consumer)
+        assertEquals(2000, clock.millis())
+    }
+}
-- 
cgit v1.2.3


From 7b2d03add3170b9142bf42c5a64aaa263773caf7 Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Thu, 30 Sep 2021 11:55:27 +0200
Subject: refactor(simulator): Separate push and pull flags

This change separates the push and pull flags in
FlowConsumerContextImpl, meaning that sources can now push directly
without pulling and vice versa.
---
 .../opendc/simulator/flow/FlowConsumerContextTest.kt    | 17 -----------------
 1 file changed, 17 deletions(-)

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
index 061ebea6..380fd38a 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
@@ -28,7 +28,6 @@ import org.junit.jupiter.api.*
 import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.internal.FlowConsumerContextImpl
 import org.opendc.simulator.flow.internal.FlowEngineImpl
-import org.opendc.simulator.flow.source.FixedFlowSource
 
 /**
  * A test suite for the [FlowConsumerContextImpl] class.
@@ -55,22 +54,6 @@ class FlowConsumerContextTest {
         engine.scheduleSync(engine.clock.millis(), context)
     }
 
-    @Test
-    fun testIntermediateFlush() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-        val consumer = FixedFlowSource(1.0, 1.0)
-
-        val logic = spyk(object : FlowConsumerLogic {})
-        val context = FlowConsumerContextImpl(engine, consumer, logic)
-        context.capacity = 1.0
-
-        context.start()
-        delay(1) // Delay 1 ms to prevent hitting the fast path
-        engine.scheduleSync(engine.clock.millis(), context)
-
-        verify(exactly = 2) { logic.onPush(any(), any(), any(), any()) }
-    }
-
     @Test
     fun testDoubleStart() = runBlockingSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
-- 
cgit v1.2.3


From b0fc93f818e5e735e972a04f5aa49e0ebe1de181 Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Thu, 30 Sep 2021 14:35:30 +0200
Subject: refactor(simulator): Remove failure callback from FlowSource

This change removes the `onFailure` method from FlowSource. Instead, the
FlowConsumer will receive the reason for failure of the source.
---
 .../simulator/flow/FlowConsumerContextTest.kt      |  31 ----
 .../org/opendc/simulator/flow/FlowForwarderTest.kt |  96 +++++++++++++
 .../flow/mux/ExclusiveFlowMultiplexerTest.kt       | 157 +++++++++++++++++++++
 .../flow/mux/MaxMinFlowMultiplexerTest.kt          | 147 +++++++++++++++++++
 .../flow/mux/SimResourceSwitchExclusiveTest.kt     | 157 ---------------------
 .../flow/mux/SimResourceSwitchMaxMinTest.kt        | 147 -------------------
 6 files changed, 400 insertions(+), 335 deletions(-)
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
 delete mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
 delete mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
index 380fd38a..f1a5cbe4 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
@@ -23,7 +23,6 @@
 package org.opendc.simulator.flow
 
 import io.mockk.*
-import kotlinx.coroutines.*
 import org.junit.jupiter.api.*
 import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.internal.FlowConsumerContextImpl
@@ -102,34 +101,4 @@ class FlowConsumerContextTest {
 
         verify(exactly = 0) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
     }
-
-    @Test
-    fun testFailureNoInfiniteLoop() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val consumer = spyk(object : FlowSource {
-            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
-                conn.close()
-                return Long.MAX_VALUE
-            }
-
-            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
-                if (event == FlowEvent.Exit) throw IllegalStateException("onEvent")
-            }
-
-            override fun onFailure(conn: FlowConnection, cause: Throwable) {
-                throw IllegalStateException("onFailure")
-            }
-        })
-
-        val logic = object : FlowConsumerLogic {}
-
-        val context = FlowConsumerContextImpl(engine, consumer, logic)
-
-        context.start()
-
-        delay(1)
-
-        verify(exactly = 1) { consumer.onFailure(any(), any()) }
-    }
 }
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index cbc48a4e..d125c638 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -219,4 +219,100 @@ internal class FlowForwarderTest {
         assertEquals(source.counters.overcommit, forwarder.counters.overcommit) { "Overcommitted work" }
         assertEquals(2000, clock.millis())
     }
+
+    @Test
+    fun testCoupledExit() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine, isCoupled = true)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        forwarder.consume(FixedFlowSource(2000.0, 1.0))
+
+        yield()
+
+        assertFalse(source.isActive)
+    }
+
+    @Test
+    fun testPullFailureCoupled() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine, isCoupled = true)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        try {
+            forwarder.consume(object : FlowSource {
+                override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                    throw IllegalStateException("Test")
+                }
+            })
+        } catch (cause: Throwable) {
+            // Ignore
+        }
+
+        yield()
+
+        assertFalse(source.isActive)
+    }
+
+    @Test
+    fun testEventFailure() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        try {
+            forwarder.consume(object : FlowSource {
+                override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                    return Long.MAX_VALUE
+                }
+
+                override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                    throw IllegalStateException("Test")
+                }
+            })
+        } catch (cause: Throwable) {
+            // Ignore
+        }
+
+        yield()
+
+        assertTrue(source.isActive)
+        source.cancel()
+    }
+
+    @Test
+    fun testEventConvergeFailure() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+        val forwarder = FlowForwarder(engine)
+        val source = FlowSink(engine, 2000.0)
+
+        launch { source.consume(forwarder) }
+
+        try {
+            forwarder.consume(object : FlowSource {
+                override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                    return Long.MAX_VALUE
+                }
+
+                override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                    if (event == FlowEvent.Converge) {
+                        throw IllegalStateException("Test")
+                    }
+                }
+            })
+        } catch (cause: Throwable) {
+            // Ignore
+        }
+
+        yield()
+
+        assertTrue(source.isActive)
+        source.cancel()
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
new file mode 100644
index 00000000..c8627446
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.mux
+
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertAll
+import org.junit.jupiter.api.assertThrows
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.*
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.FlowSourceRateAdapter
+import org.opendc.simulator.flow.source.TraceFlowSource
+
+/**
+ * Test suite for the [ForwardingFlowMultiplexer] class.
+ */
+internal class ExclusiveFlowMultiplexerTest {
+    /**
+     * Test a trace workload.
+     */
+    @Test
+    fun testTrace() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val speed = mutableListOf<Double>()
+
+        val duration = 5 * 60L
+        val workload =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+        val forwarder = FlowForwarder(engine)
+        val adapter = FlowSourceRateAdapter(forwarder, speed::add)
+        source.startConsumer(adapter)
+        switch.addOutput(forwarder)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertAll(
+            { assertEquals(listOf(0.0, 28.0, 3200.0, 0.0, 183.0, 0.0), speed) { "Correct speed" } },
+            { assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" } }
+        )
+    }
+
+    /**
+     * Test runtime workload on hypervisor.
+     */
+    @Test
+    fun testRuntimeWorkload() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = FixedFlowSource(duration * 3.2, 1.0)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertEquals(duration, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test two workloads running sequentially.
+     */
+    @Test
+    fun testTwoWorkloads() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = object : FlowSource {
+            var isFirst = true
+
+            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                when (event) {
+                    FlowEvent.Start -> isFirst = true
+                    else -> {}
+                }
+            }
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    duration
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+        provider.consume(workload)
+        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test concurrent workloads on the machine.
+     */
+    @Test
+    fun testConcurrentWorkloadFails() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        switch.addOutput(source)
+
+        switch.newInput()
+        assertThrows<IllegalStateException> { switch.newInput() }
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
new file mode 100644
index 00000000..9f6b8a2c
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.mux
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.*
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.FlowSink
+import org.opendc.simulator.flow.consume
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.TraceFlowSource
+
+/**
+ * Test suite for the [FlowMultiplexer] implementations
+ */
+internal class MaxMinFlowMultiplexerTest {
+    @Test
+    fun testSmoke() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+        val switch = MaxMinFlowMultiplexer(scheduler)
+
+        val sources = List(2) { FlowSink(scheduler, 2000.0) }
+        sources.forEach { switch.addOutput(it) }
+
+        val provider = switch.newInput()
+        val consumer = FixedFlowSource(2000.0, 1.0)
+
+        try {
+            provider.consume(consumer)
+            yield()
+        } finally {
+            switch.clear()
+        }
+    }
+
+    /**
+     * Test overcommitting of resources via the hypervisor with a single VM.
+     */
+    @Test
+    fun testOvercommittedSingle() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L
+        val workload =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+
+        val switch = MaxMinFlowMultiplexer(scheduler)
+        val provider = switch.newInput()
+
+        try {
+            switch.addOutput(FlowSink(scheduler, 3200.0))
+            provider.consume(workload)
+            yield()
+        } finally {
+            switch.clear()
+        }
+
+        assertAll(
+            { assertEquals(1113300.0, switch.counters.demand, "Requested work does not match") },
+            { assertEquals(1023300.0, switch.counters.actual, "Actual work does not match") },
+            { assertEquals(90000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(1200000, clock.millis()) }
+        )
+    }
+
+    /**
+     * Test overcommitting of resources via the hypervisor with two VMs.
+     */
+    @Test
+    fun testOvercommittedDual() = runBlockingSimulation {
+        val scheduler = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L
+        val workloadA =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+        val workloadB =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3100.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 73.0)
+                )
+            )
+
+        val switch = MaxMinFlowMultiplexer(scheduler)
+        val providerA = switch.newInput()
+        val providerB = switch.newInput()
+
+        try {
+            switch.addOutput(FlowSink(scheduler, 3200.0))
+
+            coroutineScope {
+                launch { providerA.consume(workloadA) }
+                providerB.consume(workloadB)
+            }
+
+            yield()
+        } finally {
+            switch.clear()
+        }
+        assertAll(
+            { assertEquals(2073600.0, switch.counters.demand, "Requested work does not match") },
+            { assertEquals(1053600.0, switch.counters.actual, "Granted work does not match") },
+            { assertEquals(1020000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(1200000, clock.millis()) }
+        )
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
deleted file mode 100644
index b503087e..00000000
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchExclusiveTest.kt
+++ /dev/null
@@ -1,157 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.simulator.flow.mux
-
-import kotlinx.coroutines.yield
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertAll
-import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.simulator.flow.*
-import org.opendc.simulator.flow.internal.FlowEngineImpl
-import org.opendc.simulator.flow.source.FixedFlowSource
-import org.opendc.simulator.flow.source.FlowSourceRateAdapter
-import org.opendc.simulator.flow.source.TraceFlowSource
-
-/**
- * Test suite for the [ForwardingFlowMultiplexer] class.
- */
-internal class SimResourceSwitchExclusiveTest {
-    /**
-     * Test a trace workload.
-     */
-    @Test
-    fun testTrace() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val speed = mutableListOf<Double>()
-
-        val duration = 5 * 60L
-        val workload =
-            TraceFlowSource(
-                sequenceOf(
-                    TraceFlowSource.Fragment(duration * 1000, 28.0),
-                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
-                    TraceFlowSource.Fragment(duration * 1000, 0.0),
-                    TraceFlowSource.Fragment(duration * 1000, 183.0)
-                ),
-            )
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-        val forwarder = FlowForwarder(engine)
-        val adapter = FlowSourceRateAdapter(forwarder, speed::add)
-        source.startConsumer(adapter)
-        switch.addOutput(forwarder)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-
-        assertAll(
-            { assertEquals(listOf(0.0, 28.0, 3200.0, 0.0, 183.0, 0.0), speed) { "Correct speed" } },
-            { assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" } }
-        )
-    }
-
-    /**
-     * Test runtime workload on hypervisor.
-     */
-    @Test
-    fun testRuntimeWorkload() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L * 1000
-        val workload = FixedFlowSource(duration * 3.2, 1.0)
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-
-        assertEquals(duration, clock.millis()) { "Took enough time" }
-    }
-
-    /**
-     * Test two workloads running sequentially.
-     */
-    @Test
-    fun testTwoWorkloads() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L * 1000
-        val workload = object : FlowSource {
-            var isFirst = true
-
-            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
-                when (event) {
-                    FlowEvent.Start -> isFirst = true
-                    else -> {}
-                }
-            }
-
-            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
-                return if (isFirst) {
-                    isFirst = false
-                    conn.push(1.0)
-                    duration
-                } else {
-                    conn.close()
-                    Long.MAX_VALUE
-                }
-            }
-        }
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-        provider.consume(workload)
-        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
-    }
-
-    /**
-     * Test concurrent workloads on the machine.
-     */
-    @Test
-    fun testConcurrentWorkloadFails() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        switch.newInput()
-        assertThrows<IllegalStateException> { switch.newInput() }
-    }
-}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt
deleted file mode 100644
index 089a8d78..00000000
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/SimResourceSwitchMaxMinTest.kt
+++ /dev/null
@@ -1,147 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.simulator.flow.mux
-
-import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.yield
-import org.junit.jupiter.api.*
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.simulator.flow.FlowSink
-import org.opendc.simulator.flow.consume
-import org.opendc.simulator.flow.internal.FlowEngineImpl
-import org.opendc.simulator.flow.source.FixedFlowSource
-import org.opendc.simulator.flow.source.TraceFlowSource
-
-/**
- * Test suite for the [FlowMultiplexer] implementations
- */
-internal class SimResourceSwitchMaxMinTest {
-    @Test
-    fun testSmoke() = runBlockingSimulation {
-        val scheduler = FlowEngineImpl(coroutineContext, clock)
-        val switch = MaxMinFlowMultiplexer(scheduler)
-
-        val sources = List(2) { FlowSink(scheduler, 2000.0) }
-        sources.forEach { switch.addOutput(it) }
-
-        val provider = switch.newInput()
-        val consumer = FixedFlowSource(2000.0, 1.0)
-
-        try {
-            provider.consume(consumer)
-            yield()
-        } finally {
-            switch.clear()
-        }
-    }
-
-    /**
-     * Test overcommitting of resources via the hypervisor with a single VM.
-     */
-    @Test
-    fun testOvercommittedSingle() = runBlockingSimulation {
-        val scheduler = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L
-        val workload =
-            TraceFlowSource(
-                sequenceOf(
-                    TraceFlowSource.Fragment(duration * 1000, 28.0),
-                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
-                    TraceFlowSource.Fragment(duration * 1000, 0.0),
-                    TraceFlowSource.Fragment(duration * 1000, 183.0)
-                ),
-            )
-
-        val switch = MaxMinFlowMultiplexer(scheduler)
-        val provider = switch.newInput()
-
-        try {
-            switch.addOutput(FlowSink(scheduler, 3200.0))
-            provider.consume(workload)
-            yield()
-        } finally {
-            switch.clear()
-        }
-
-        assertAll(
-            { assertEquals(1113300.0, switch.counters.demand, "Requested work does not match") },
-            { assertEquals(1023300.0, switch.counters.actual, "Actual work does not match") },
-            { assertEquals(90000.0, switch.counters.overcommit, "Overcommitted work does not match") },
-            { assertEquals(1200000, clock.millis()) }
-        )
-    }
-
-    /**
-     * Test overcommitting of resources via the hypervisor with two VMs.
-     */
-    @Test
-    fun testOvercommittedDual() = runBlockingSimulation {
-        val scheduler = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L
-        val workloadA =
-            TraceFlowSource(
-                sequenceOf(
-                    TraceFlowSource.Fragment(duration * 1000, 28.0),
-                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
-                    TraceFlowSource.Fragment(duration * 1000, 0.0),
-                    TraceFlowSource.Fragment(duration * 1000, 183.0)
-                ),
-            )
-        val workloadB =
-            TraceFlowSource(
-                sequenceOf(
-                    TraceFlowSource.Fragment(duration * 1000, 28.0),
-                    TraceFlowSource.Fragment(duration * 1000, 3100.0),
-                    TraceFlowSource.Fragment(duration * 1000, 0.0),
-                    TraceFlowSource.Fragment(duration * 1000, 73.0)
-                )
-            )
-
-        val switch = MaxMinFlowMultiplexer(scheduler)
-        val providerA = switch.newInput()
-        val providerB = switch.newInput()
-
-        try {
-            switch.addOutput(FlowSink(scheduler, 3200.0))
-
-            coroutineScope {
-                launch { providerA.consume(workloadA) }
-                providerB.consume(workloadB)
-            }
-
-            yield()
-        } finally {
-            switch.clear()
-        }
-        assertAll(
-            { assertEquals(2073600.0, switch.counters.demand, "Requested work does not match") },
-            { assertEquals(1053600.0, switch.counters.actual, "Granted work does not match") },
-            { assertEquals(1020000.0, switch.counters.overcommit, "Overcommitted work does not match") },
-            { assertEquals(1200000, clock.millis()) }
-        )
-    }
-}
-- 
cgit v1.2.3


From 4f5a1f88d0c6aa19ce4cab0ec7b9b13a24c92fbe Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Thu, 30 Sep 2021 14:45:42 +0200
Subject: refactor(simulator): Remove capacity event

This change removes the Capacity entry from FlowEvent. Since the source
is always pulled on a capacity change, we do not need a separate event
for this.
---
 .../test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt    | 2 +-
 .../src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt      | 2 +-
 .../src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt           | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
index f1a5cbe4..fe39eb2c 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
@@ -99,6 +99,6 @@ class FlowConsumerContextTest {
         context.start()
         context.capacity = 4200.0
 
-        verify(exactly = 0) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+        verify(exactly = 1) { consumer.onPull(any(), any(), any()) }
     }
 }
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index d125c638..7fae918a 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -197,7 +197,7 @@ internal class FlowForwarderTest {
         }
 
         assertEquals(3000, clock.millis())
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+        verify(exactly = 1) { consumer.onPull(any(), any(), any()) }
     }
 
     @Test
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
index 010a985e..5d579e5d 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
@@ -67,7 +67,7 @@ internal class FlowSinkTest {
             provider.capacity = 0.5
         }
         assertEquals(3000, clock.millis())
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Capacity) }
+        verify(exactly = 1) { consumer.onPull(any(), any(), any()) }
     }
 
     @Test
-- 
cgit v1.2.3


From a2ce07026bf3ef17326e72f395dfa2dd9d9b17be Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Thu, 30 Sep 2021 15:37:35 +0200
Subject: refactor(simulator): Create separate callbacks for remaining events

This change creates separate callbacks for the remaining events:
onStart, onStop and onConverge.
---
 .../org/opendc/simulator/flow/FlowForwarderTest.kt | 39 +++++++++++-----------
 .../org/opendc/simulator/flow/FlowSinkTest.kt      | 25 +++++++-------
 .../flow/mux/ExclusiveFlowMultiplexerTest.kt       |  7 ++--
 3 files changed, 34 insertions(+), 37 deletions(-)

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index 7fae918a..3690e681 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -22,10 +22,10 @@
 
 package org.opendc.simulator.flow
 
-import io.mockk.spyk
-import io.mockk.verify
+import io.mockk.*
 import kotlinx.coroutines.*
 import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
 import org.opendc.simulator.core.runBlockingSimulation
@@ -122,7 +122,7 @@ internal class FlowForwarderTest {
         forwarder.startConsumer(consumer)
         forwarder.cancel()
 
-        verify(exactly = 0) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+        verify(exactly = 0) { consumer.onStop(any(), any(), any()) }
     }
 
     @Test
@@ -139,8 +139,8 @@ internal class FlowForwarderTest {
         yield()
         forwarder.cancel()
 
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Start) }
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+        verify(exactly = 1) { consumer.onStart(any(), any()) }
+        verify(exactly = 1) { consumer.onStop(any(), any(), any()) }
     }
 
     @Test
@@ -157,8 +157,8 @@ internal class FlowForwarderTest {
         yield()
         source.cancel()
 
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Start) }
-        verify(exactly = 1) { consumer.onEvent(any(), any(), FlowEvent.Exit) }
+        verify(exactly = 1) { consumer.onStart(any(), any()) }
+        verify(exactly = 1) { consumer.onStop(any(), any(), any()) }
     }
 
     @Test
@@ -182,22 +182,23 @@ internal class FlowForwarderTest {
     }
 
     @Test
+    @Disabled // Due to Kotlin bug: https://github.com/mockk/mockk/issues/368
     fun testAdjustCapacity() = runBlockingSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
-        val source = FlowSink(engine, 1.0)
+        val sink = FlowSink(engine, 1.0)
 
-        val consumer = spyk(FixedFlowSource(2.0, 1.0))
-        source.startConsumer(forwarder)
+        val source = spyk(FixedFlowSource(2.0, 1.0))
+        sink.startConsumer(forwarder)
 
         coroutineScope {
-            launch { forwarder.consume(consumer) }
+            launch { forwarder.consume(source) }
             delay(1000)
-            source.capacity = 0.5
+            sink.capacity = 0.5
         }
 
         assertEquals(3000, clock.millis())
-        verify(exactly = 1) { consumer.onPull(any(), any(), any()) }
+        verify(exactly = 1) { source.onPull(any(), any(), any()) }
     }
 
     @Test
@@ -259,7 +260,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testEventFailure() = runBlockingSimulation {
+    fun testStartFailure() = runBlockingSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -272,7 +273,7 @@ internal class FlowForwarderTest {
                     return Long.MAX_VALUE
                 }
 
-                override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+                override fun onStart(conn: FlowConnection, now: Long) {
                     throw IllegalStateException("Test")
                 }
             })
@@ -287,7 +288,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testEventConvergeFailure() = runBlockingSimulation {
+    fun testConvergeFailure() = runBlockingSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -300,10 +301,8 @@ internal class FlowForwarderTest {
                     return Long.MAX_VALUE
                 }
 
-                override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
-                    if (event == FlowEvent.Converge) {
-                        throw IllegalStateException("Test")
-                    }
+                override fun onConverge(conn: FlowConnection, now: Long, delta: Long) {
+                    throw IllegalStateException("Test")
                 }
             })
         } catch (cause: Throwable) {
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
index 5d579e5d..70c75864 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
@@ -22,8 +22,6 @@
 
 package org.opendc.simulator.flow
 
-import io.mockk.every
-import io.mockk.mockk
 import io.mockk.spyk
 import io.mockk.verify
 import kotlinx.coroutines.*
@@ -67,7 +65,7 @@ internal class FlowSinkTest {
             provider.capacity = 0.5
         }
         assertEquals(3000, clock.millis())
-        verify(exactly = 1) { consumer.onPull(any(), any(), any()) }
+        verify(exactly = 3) { consumer.onPull(any(), any(), any()) }
     }
 
     @Test
@@ -102,7 +100,7 @@ internal class FlowSinkTest {
                 return Long.MAX_VALUE
             }
 
-            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
+            override fun onStart(conn: FlowConnection, now: Long) {
                 conn.pull()
             }
         }
@@ -120,11 +118,8 @@ internal class FlowSinkTest {
         val consumer = object : FlowSource {
             var isFirst = true
 
-            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
-                when (event) {
-                    FlowEvent.Start -> resCtx = conn
-                    else -> {}
-                }
+            override fun onStart(conn: FlowConnection, now: Long) {
+                resCtx = conn
             }
 
             override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
@@ -154,9 +149,15 @@ internal class FlowSinkTest {
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
 
-        val consumer = mockk<FlowSource>(relaxUnitFun = true)
-        every { consumer.onEvent(any(), any(), eq(FlowEvent.Start)) }
-            .throws(IllegalStateException())
+        val consumer = object : FlowSource {
+            override fun onStart(conn: FlowConnection, now: Long) {
+                throw IllegalStateException("Hi")
+            }
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return Long.MAX_VALUE
+            }
+        }
 
         assertThrows<IllegalStateException> {
             provider.consume(consumer)
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
index c8627446..3475f027 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
@@ -108,11 +108,8 @@ internal class ExclusiveFlowMultiplexerTest {
         val workload = object : FlowSource {
             var isFirst = true
 
-            override fun onEvent(conn: FlowConnection, now: Long, event: FlowEvent) {
-                when (event) {
-                    FlowEvent.Start -> isFirst = true
-                    else -> {}
-                }
+            override fun onStart(conn: FlowConnection, now: Long) {
+                isFirst = true
             }
 
             override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
-- 
cgit v1.2.3


From 559ac2327b8aa319fb8ab4558d4f4aa3382349f4 Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Thu, 30 Sep 2021 16:27:45 +0200
Subject: perf(simulator): Make convergence callback optional

This change adds two new properties for controlling whether the
convergence callbacks of the source and consumer respectively should be
invoked. This saves a lot of unnecessary calls for stages that do not
have any implementation of the `onConvergence` method.
---
 .../src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt    | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index 3690e681..d548451f 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -297,6 +297,10 @@ internal class FlowForwarderTest {
 
         try {
             forwarder.consume(object : FlowSource {
+                override fun onStart(conn: FlowConnection, now: Long) {
+                    conn.shouldSourceConverge = true
+                }
+
                 override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
                     return Long.MAX_VALUE
                 }
-- 
cgit v1.2.3


From 081221684fb826ab5a00c1d8cc5a9886b9e2203c Mon Sep 17 00:00:00 2001
From: Fabian Mastenbroek <mail.fabianm@gmail.com>
Date: Fri, 1 Oct 2021 22:04:35 +0200
Subject: feat(simulator): Expose CPU time counters directly on hypervisor

This change adds a new interface to the SimHypervisor interface that
exposes the CPU time counters directly. These are derived from the flow
counters and will be used by SimHost to expose them via telemetry.
---
 .../org/opendc/simulator/flow/FlowForwarderTest.kt |   2 +-
 .../flow/mux/ExclusiveFlowMultiplexerTest.kt       | 154 ---------------------
 .../flow/mux/ForwardingFlowMultiplexerTest.kt      | 154 +++++++++++++++++++++
 .../flow/mux/MaxMinFlowMultiplexerTest.kt          |  12 +-
 4 files changed, 162 insertions(+), 160 deletions(-)
 delete mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
 create mode 100644 opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt

(limited to 'opendc-simulator/opendc-simulator-flow/src/test')

diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index d548451f..12e72b8f 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -217,7 +217,7 @@ internal class FlowForwarderTest {
         assertEquals(2.0, source.counters.actual)
         assertEquals(source.counters.actual, forwarder.counters.actual) { "Actual work" }
         assertEquals(source.counters.demand, forwarder.counters.demand) { "Work demand" }
-        assertEquals(source.counters.overcommit, forwarder.counters.overcommit) { "Overcommitted work" }
+        assertEquals(source.counters.remaining, forwarder.counters.remaining) { "Overcommitted work" }
         assertEquals(2000, clock.millis())
     }
 
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
deleted file mode 100644
index 3475f027..00000000
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ExclusiveFlowMultiplexerTest.kt
+++ /dev/null
@@ -1,154 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.simulator.flow.mux
-
-import kotlinx.coroutines.yield
-import org.junit.jupiter.api.Assertions.assertEquals
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertAll
-import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.simulator.flow.*
-import org.opendc.simulator.flow.internal.FlowEngineImpl
-import org.opendc.simulator.flow.source.FixedFlowSource
-import org.opendc.simulator.flow.source.FlowSourceRateAdapter
-import org.opendc.simulator.flow.source.TraceFlowSource
-
-/**
- * Test suite for the [ForwardingFlowMultiplexer] class.
- */
-internal class ExclusiveFlowMultiplexerTest {
-    /**
-     * Test a trace workload.
-     */
-    @Test
-    fun testTrace() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val speed = mutableListOf<Double>()
-
-        val duration = 5 * 60L
-        val workload =
-            TraceFlowSource(
-                sequenceOf(
-                    TraceFlowSource.Fragment(duration * 1000, 28.0),
-                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
-                    TraceFlowSource.Fragment(duration * 1000, 0.0),
-                    TraceFlowSource.Fragment(duration * 1000, 183.0)
-                ),
-            )
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-        val forwarder = FlowForwarder(engine)
-        val adapter = FlowSourceRateAdapter(forwarder, speed::add)
-        source.startConsumer(adapter)
-        switch.addOutput(forwarder)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-
-        assertAll(
-            { assertEquals(listOf(0.0, 28.0, 3200.0, 0.0, 183.0, 0.0), speed) { "Correct speed" } },
-            { assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" } }
-        )
-    }
-
-    /**
-     * Test runtime workload on hypervisor.
-     */
-    @Test
-    fun testRuntimeWorkload() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L * 1000
-        val workload = FixedFlowSource(duration * 3.2, 1.0)
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-
-        assertEquals(duration, clock.millis()) { "Took enough time" }
-    }
-
-    /**
-     * Test two workloads running sequentially.
-     */
-    @Test
-    fun testTwoWorkloads() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val duration = 5 * 60L * 1000
-        val workload = object : FlowSource {
-            var isFirst = true
-
-            override fun onStart(conn: FlowConnection, now: Long) {
-                isFirst = true
-            }
-
-            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
-                return if (isFirst) {
-                    isFirst = false
-                    conn.push(1.0)
-                    duration
-                } else {
-                    conn.close()
-                    Long.MAX_VALUE
-                }
-            }
-        }
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        val provider = switch.newInput()
-        provider.consume(workload)
-        yield()
-        provider.consume(workload)
-        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
-    }
-
-    /**
-     * Test concurrent workloads on the machine.
-     */
-    @Test
-    fun testConcurrentWorkloadFails() = runBlockingSimulation {
-        val engine = FlowEngineImpl(coroutineContext, clock)
-
-        val switch = ForwardingFlowMultiplexer(engine)
-        val source = FlowSink(engine, 3200.0)
-
-        switch.addOutput(source)
-
-        switch.newInput()
-        assertThrows<IllegalStateException> { switch.newInput() }
-    }
-}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt
new file mode 100644
index 00000000..187dacd9
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.opendc.simulator.flow.mux
+
+import kotlinx.coroutines.yield
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertAll
+import org.junit.jupiter.api.assertThrows
+import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.flow.*
+import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.flow.source.FlowSourceRateAdapter
+import org.opendc.simulator.flow.source.TraceFlowSource
+
+/**
+ * Test suite for the [ForwardingFlowMultiplexer] class.
+ */
+internal class ForwardingFlowMultiplexerTest {
+    /**
+     * Test a trace workload.
+     */
+    @Test
+    fun testTrace() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val speed = mutableListOf<Double>()
+
+        val duration = 5 * 60L
+        val workload =
+            TraceFlowSource(
+                sequenceOf(
+                    TraceFlowSource.Fragment(duration * 1000, 28.0),
+                    TraceFlowSource.Fragment(duration * 1000, 3500.0),
+                    TraceFlowSource.Fragment(duration * 1000, 0.0),
+                    TraceFlowSource.Fragment(duration * 1000, 183.0)
+                ),
+            )
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+        val forwarder = FlowForwarder(engine)
+        val adapter = FlowSourceRateAdapter(forwarder, speed::add)
+        source.startConsumer(adapter)
+        forwarder.startConsumer(switch.newOutput())
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertAll(
+            { assertEquals(listOf(0.0, 28.0, 3200.0, 0.0, 183.0, 0.0), speed) { "Correct speed" } },
+            { assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" } }
+        )
+    }
+
+    /**
+     * Test runtime workload on hypervisor.
+     */
+    @Test
+    fun testRuntimeWorkload() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = FixedFlowSource(duration * 3.2, 1.0)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        source.startConsumer(switch.newOutput())
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+
+        assertEquals(duration, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test two workloads running sequentially.
+     */
+    @Test
+    fun testTwoWorkloads() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val duration = 5 * 60L * 1000
+        val workload = object : FlowSource {
+            var isFirst = true
+
+            override fun onStart(conn: FlowConnection, now: Long) {
+                isFirst = true
+            }
+
+            override fun onPull(conn: FlowConnection, now: Long, delta: Long): Long {
+                return if (isFirst) {
+                    isFirst = false
+                    conn.push(1.0)
+                    duration
+                } else {
+                    conn.close()
+                    Long.MAX_VALUE
+                }
+            }
+        }
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        source.startConsumer(switch.newOutput())
+
+        val provider = switch.newInput()
+        provider.consume(workload)
+        yield()
+        provider.consume(workload)
+        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
+    }
+
+    /**
+     * Test concurrent workloads on the machine.
+     */
+    @Test
+    fun testConcurrentWorkloadFails() = runBlockingSimulation {
+        val engine = FlowEngineImpl(coroutineContext, clock)
+
+        val switch = ForwardingFlowMultiplexer(engine)
+        val source = FlowSink(engine, 3200.0)
+
+        source.startConsumer(switch.newOutput())
+
+        switch.newInput()
+        assertThrows<IllegalStateException> { switch.newInput() }
+    }
+}
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
index 9f6b8a2c..6e2cdb98 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
@@ -44,7 +44,7 @@ internal class MaxMinFlowMultiplexerTest {
         val switch = MaxMinFlowMultiplexer(scheduler)
 
         val sources = List(2) { FlowSink(scheduler, 2000.0) }
-        sources.forEach { switch.addOutput(it) }
+        sources.forEach { it.startConsumer(switch.newOutput()) }
 
         val provider = switch.newInput()
         val consumer = FixedFlowSource(2000.0, 1.0)
@@ -76,10 +76,11 @@ internal class MaxMinFlowMultiplexerTest {
             )
 
         val switch = MaxMinFlowMultiplexer(scheduler)
+        val sink = FlowSink(scheduler, 3200.0)
         val provider = switch.newInput()
 
         try {
-            switch.addOutput(FlowSink(scheduler, 3200.0))
+            sink.startConsumer(switch.newOutput())
             provider.consume(workload)
             yield()
         } finally {
@@ -89,7 +90,7 @@ internal class MaxMinFlowMultiplexerTest {
         assertAll(
             { assertEquals(1113300.0, switch.counters.demand, "Requested work does not match") },
             { assertEquals(1023300.0, switch.counters.actual, "Actual work does not match") },
-            { assertEquals(90000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(2816700.0, switch.counters.remaining, "Remaining capacity does not match") },
             { assertEquals(1200000, clock.millis()) }
         )
     }
@@ -122,11 +123,12 @@ internal class MaxMinFlowMultiplexerTest {
             )
 
         val switch = MaxMinFlowMultiplexer(scheduler)
+        val sink = FlowSink(scheduler, 3200.0)
         val providerA = switch.newInput()
         val providerB = switch.newInput()
 
         try {
-            switch.addOutput(FlowSink(scheduler, 3200.0))
+            sink.startConsumer(switch.newOutput())
 
             coroutineScope {
                 launch { providerA.consume(workloadA) }
@@ -140,7 +142,7 @@ internal class MaxMinFlowMultiplexerTest {
         assertAll(
             { assertEquals(2073600.0, switch.counters.demand, "Requested work does not match") },
             { assertEquals(1053600.0, switch.counters.actual, "Granted work does not match") },
-            { assertEquals(1020000.0, switch.counters.overcommit, "Overcommitted work does not match") },
+            { assertEquals(2786400.0, switch.counters.remaining, "Remaining capacity does not match") },
             { assertEquals(1200000, clock.millis()) }
         )
     }
-- 
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