Test CancellationGroup

tests/NScatterGather.Tests/Internals/CancellationGroupTests.cs

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+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace NScatterGather.Internals
+{
+    public class CancellationGroupTests
+    {
+        [Fact]
+        public void With_already_canceled_token()
+        {
+            var group = new CancellationGroup(new CancellationToken(canceled: true));
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+        }
+
+        [Fact]
+        public void Cancel_with_one_cancellation_token()
+        {
+            using var cts = new CancellationTokenSource();
+            var group = new CancellationGroup(cts.Token);
+
+            Assert.False(group.CancellationToken.IsCancellationRequested);
+
+            cts.Cancel();
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+        }
+
+        [Fact]
+        public void Cancel_with_multiple_cancellation_tokens()
+        {
+            using var cts1 = new CancellationTokenSource();
+            using var cts2 = new CancellationTokenSource();
+
+            var group = new CancellationGroup(new[] { cts1.Token, cts2.Token });
+
+            Assert.False(group.CancellationToken.IsCancellationRequested);
+
+            cts1.Cancel();
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+
+            cts2.Cancel();
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+        }
+
+        [Fact]
+        public async Task Can_be_canceled()
+        {
+            var received = false;
+
+            using var cts1 = new CancellationTokenSource();
+            using var cts2 = new CancellationTokenSource();
+
+            var group = new CancellationGroup(new[] { cts1.Token, cts2.Token });
+
+            group.OnCanceled += () => received = true;
+
+            group.Cancel();
+            await Task.Yield();
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+            Assert.True(received);
+        }
+
+        [Fact]
+        public async Task Cancellation_emits_event()
+        {
+            var received = false;
+
+            using var cts = new CancellationTokenSource();
+            var group = new CancellationGroup(cts.Token);
+
+            group.OnCanceled += () => received = true;
+
+            cts.Cancel();
+            await Task.Yield();
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+            Assert.True(received);
+        }
+
+        [Fact(Timeout = 6000)]
+        public async Task Cancellation_via_timeout()
+        {
+            var received = false;
+            var delay = TimeSpan.FromSeconds(2);
+
+            using var cts = new CancellationTokenSource(delay);
+            var group = new CancellationGroup(cts.Token);
+
+            group.OnCanceled += () => received = true;
+
+            await Task.Delay(delay + delay);
+
+            Assert.True(group.CancellationToken.IsCancellationRequested);
+            Assert.True(received);
+        }
+
+        [Fact]
+        public void Can_be_disposed()
+        {
+            using var cts = new CancellationTokenSource();
+            var group = new CancellationGroup(cts.Token);
+
+            group.Dispose();
+
+            Assert.Throws<ObjectDisposedException>(() => group.Cancel());
+        }
+    }
+}