refactor(sim/core): Re-implement SimulationScheduler as Dispatcher

This change updates the `SimulationScheduler` class to implement the
`Dispatcher` interface from the OpenDC Common module, so that OpenDC
modules only need to depend on the common module for dispatching future
task (possibly in simulation).

2 files changed, 110 insertions, 11 deletions

diff --git a/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/SimulationSchedulerTest.kt b/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/SimulationDispatcherTest.kt
index eca3b582..600102be 100644
--- a/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/SimulationSchedulerTest.kt
+++ b/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/SimulationDispatcherTest.kt
@@ -28,15 +28,15 @@ import org.junit.jupiter.api.assertThrows
 import java.time.Instant
 
 /**
- * Test suite for the [SimulationScheduler] class.
+ * Test suite for the [SimulationDispatcher] class.
  */
-class SimulationSchedulerTest {
+class SimulationDispatcherTest {
     /**
-     * Test the basic functionality of [SimulationScheduler.runCurrent].
+     * Test the basic functionality of [SimulationDispatcher.runCurrent].
      */
     @Test
     fun testRunCurrent() {
-        val scheduler = SimulationScheduler()
+        val scheduler = SimulationDispatcher()
         var count = 0
 
         scheduler.schedule(1) { count += 1 }
@@ -58,11 +58,11 @@ class SimulationSchedulerTest {
     }
 
     /**
-     * Test the clock of the [SimulationScheduler].
+     * Test the clock of the [SimulationDispatcher].
      */
     @Test
     fun testClock() {
-        val scheduler = SimulationScheduler()
+        val scheduler = SimulationDispatcher()
         var count = 0
 
         scheduler.schedule(1) { count += 1 }
@@ -70,8 +70,8 @@ class SimulationSchedulerTest {
 
         scheduler.advanceBy(2)
         assertEquals(2, scheduler.currentTime)
-        assertEquals(2, scheduler.clock.millis())
-        assertEquals(Instant.ofEpochMilli(2), scheduler.clock.instant())
+        assertEquals(2, scheduler.timeSource.millis())
+        assertEquals(Instant.ofEpochMilli(2), scheduler.timeSource.instant())
     }
 
     /**
@@ -79,7 +79,7 @@ class SimulationSchedulerTest {
      */
     @Test
     fun testAdvanceByLargeDelays() {
-        val scheduler = SimulationScheduler()
+        val scheduler = SimulationDispatcher()
         var count = 0
 
         scheduler.schedule(1) { count += 1 }
@@ -87,10 +87,11 @@ class SimulationSchedulerTest {
         scheduler.advanceBy(10)
 
         scheduler.schedule(Long.MAX_VALUE) { count += 1 }
+        scheduler.scheduleCancellable(Long.MAX_VALUE) { count += 1 }
         scheduler.schedule(100_000_000) { count += 1 }
 
         scheduler.advanceUntilIdle()
-        assertEquals(3, count)
+        assertEquals(4, count)
     }
 
     /**
@@ -98,7 +99,7 @@ class SimulationSchedulerTest {
      */
     @Test
     fun testNegativeDelays() {
-        val scheduler = SimulationScheduler()
+        val scheduler = SimulationDispatcher()
 
         assertThrows<IllegalArgumentException> { scheduler.schedule(-100) { } }
         assertThrows<IllegalArgumentException> { scheduler.advanceBy(-100) }
diff --git a/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/kotlin/SimulationBuildersTest.kt b/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/kotlin/SimulationBuildersTest.kt
new file mode 100644
index 00000000..26419a50
--- /dev/null
+++ b/opendc-simulator/opendc-simulator-core/src/test/kotlin/org/opendc/simulator/kotlin/SimulationBuildersTest.kt
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2022 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.kotlin
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.suspendCancellableCoroutine
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+
+/**
+ * Test suite for the Kotlin simulation builders.
+ */
+class SimulationBuildersTest {
+    @Test
+    fun testDelay() = runSimulation {
+        assertEquals(0, currentTime)
+        delay(100)
+        assertEquals(100, currentTime)
+    }
+
+    @Test
+    fun testController() = runSimulation {
+        var completed = false
+
+        launch {
+            delay(20)
+            completed = true
+        }
+
+        advanceBy(10)
+        assertFalse(completed)
+        advanceBy(11)
+        assertTrue(completed)
+
+        completed = false
+        launch { completed = true }
+        runCurrent()
+        assertTrue(completed)
+    }
+
+    @Test
+    fun testFailOnActiveJobs() {
+        assertThrows<IllegalStateException> {
+            runSimulation {
+                launch { suspendCancellableCoroutine {} }
+            }
+        }
+    }
+
+    @Test
+    fun testPropagateException() {
+        assertThrows<IllegalStateException> {
+            runSimulation {
+                throw IllegalStateException("Test")
+            }
+        }
+    }
+
+    @Test
+    fun testInvalidDispatcher() {
+        assertThrows<IllegalArgumentException> {
+            runSimulation(Dispatchers.Default) { }
+        }
+    }
+
+    @Test
+    fun testExistingJob() {
+        runSimulation(Job()) {
+            delay(10)
+        }
+    }
+}