More Test Task runner features & tests

Author: akarnokd

async-enumerable-dotnet-test/AmbTest.cs

@@ -3,6 +3,7 @@
 // See LICENSE file in the project root for full license information.
 
 using System;
+using System.Runtime.CompilerServices;
 using Xunit;
 using async_enumerable_dotnet;
 using System.Threading;
@@ -83,5 +84,81 @@ await AsyncEnumerable.Amb(
 
             Assert.Equal(129, disposed);
         }
+
+        [Fact]
+        public async void First_Win_Sync()
+        {
+            var ttr = new TestTaskRunner();
+
+            var t = AsyncEnumerable.Amb(
+                AsyncEnumerable.Range(1, 5)
+                    .DoOnNext(async v => { await ttr.CreateCompleteTask(500); }),
+                AsyncEnumerable.Range(6, 5)
+                    .DoOnNext(async v => { await ttr.CreateCompleteTask(1000); })
+            )
+                .GetAsyncEnumerator()
+            ;
+
+            try
+            {
+                for (var i = 1; i <= 5; i++)
+                {
+                    var t0 = t.MoveNextAsync();
+
+                    await ttr.TaskQueued();
+
+                    ttr.AdvanceTimeBy(500);
+
+                    await t0;
+
+                    Assert.Equal(i, t.Current);
+                }
+                
+                Assert.False(await t.MoveNextAsync());
+            }
+            finally
+            {
+                await t.DisposeAsync();
+            }
+
+        }
+        
+        [Fact]
+        public async void Second_Win_Sync()
+        {
+            var ttr = new TestTaskRunner();
+
+            var t = AsyncEnumerable.Amb(
+                        AsyncEnumerable.Range(1, 5)
+                            .DoOnNext(async v => { await ttr.CreateCompleteTask(1000); }),
+                        AsyncEnumerable.Range(6, 5)
+                            .DoOnNext(async v => { await ttr.CreateCompleteTask(500); })
+                    )
+                    .GetAsyncEnumerator()
+                ;
+
+            try
+            {
+                for (var i = 6; i <= 10; i++)
+                {
+                    var t0 = t.MoveNextAsync();
+
+                    await ttr.TaskQueued();
+
+                    ttr.AdvanceTimeBy(500);
+
+                    await t0;
+
+                    Assert.Equal(i, t.Current);
+                }
+                
+                Assert.False(await t.MoveNextAsync());
+            }
+            finally
+            {
+                await t.DisposeAsync();
+            }
+
+        }
     }
 }

async-enumerable-dotnet/TestTaskRunner.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
+using async_enumerable_dotnet.impl;
 
 namespace async_enumerable_dotnet
 {
@@ -49,6 +50,11 @@ public bool HasTasks
             }
         }
 
+        /// <summary>
+        /// Signaled when a task queue becomes non-empty.
+        /// </summary>
+        private TaskCompletionSource<bool> _taskQueued;
+
         /// <summary>
         /// Construct a fresh TestTaskRunner with the given
         /// (optional) start virtual time.
@@ -60,6 +66,16 @@ public TestTaskRunner(long startTime = 0L)
             _queue = new SortedList<IndexDueTime, TaskTask>(IndexDueTimeComparer.Default);
         }
 
+        /// <summary>
+        /// Signals when the first task has been queued.
+        /// </summary>
+        /// <returns>The task to await for the queue to become non-empty.</returns>
+        public async Task TaskQueued()
+        {
+            await ResumeHelper.Await(ref _taskQueued);
+            ResumeHelper.Clear(ref _taskQueued);
+        }
+        
         /// <summary>
         /// Advance the virtual time by the given amount and
         /// signal all timed tasks in the meantime.
@@ -109,6 +125,8 @@ private void Enqueue(TaskTask task)
                     DueTime = task.DueTime
                 }, task);
             }
+
+            ResumeHelper.Resume(ref _taskQueued);
         }
 
         /// <summary>