RepeatAsync

Author: pascal-libaud

changelog.md

@@ -17,6 +17,7 @@ Initial version.
 	 - Add IntersectByAsync
 	 - Add JoinAsync
 	 - Add OrderAsync
+	 - Add RepeatAsync
 	 - Add SkipAsync
 	 - Add SkipLastAsync
 	 - Add SkipWhileAsync

src/AsyncLinqR.Tests/RepeatAsyncTest.cs

@@ -0,0 +1,39 @@
+namespace AsyncLinqR.Tests;
+
+public class RepeatAsyncTest
+{
+    [Fact]
+    public async Task RepeatAsync_should_work_as_expected()
+    {
+        var result = await AsyncLinq.RepeatAsync("Patin", 2).ToListAsync();
+        var expected = new List<string> { "Patin", "Patin" };
+
+        result.Should().BeEquivalentTo(expected);
+    }
+
+    [Fact]
+    public async Task RepeatAsync_should_be_empty_when_count_is_zero()
+    {
+        Assert.Empty(await AsyncLinq.RepeatAsync("Patin", 0).ToListAsync());
+    }
+
+    [Fact]
+    public async Task RepeatAsync_should_cancel_with_its_cancellation_token()
+    {
+        var token = new CancellationTokenSource();
+        await token.CancelAsync();
+
+        var sut = async () => await AsyncLinq.RepeatAsync("Patin", 2, token.Token).ToListAsync();
+        await sut.Should().ThrowAsync<OperationCanceledException>();
+    }
+
+    [Fact]
+    public async Task RepeatAsync_should_receive_cancellation_token_and_cancel()
+    {
+        var token = new CancellationTokenSource();
+        await token.CancelAsync();
+
+        var sut = async () => await AsyncLinq.RepeatAsync("Patin", 2, token.Token).ToListAsync(token.Token);
+        await sut.Should().ThrowAsync<OperationCanceledException>();
+    }
+}

src/AsyncLinqR/RepeatAsync.cs

@@ -0,0 +1,15 @@
+namespace AsyncLinqR;
+
+public static partial class AsyncLinq
+{
+    public static async IAsyncEnumerable<T> RepeatAsync<T>(T element, int count, [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        await Task.Yield();
+        cancellationToken.ThrowIfCancellationRequested();
+        while (count-- > 0)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            yield return element;
+        }
+    }
+}

src/AsyncLinqR/_Todo.cs

@@ -1,6 +1,4 @@
 // TODO : Créer les méthodes ci-dessous
 
-// RepeatAsync
-
 // Nouveautés .Net 9
 // Enumerable.CountBy, AggregateBy