Allow IAsyncEnumerable for ValueSource/TestCaseSource

documentation/NUnit1015.md

@@ -1,6 +1,6 @@
 # NUnit1015
 
-## The source type does not implement IEnumerable
+## The source type does not implement I(Async)Enumerable
 
 | Topic    | Value
 | :--      | :--
@@ -12,7 +12,7 @@
 
 ## Description
 
-The source type must implement IEnumerable in order to provide test cases.
+The source type must implement I(Async)Enumerable in order to provide test cases.
 
 ## Motivation
 
@@ -45,13 +45,13 @@ class DivideCases
 
 ### Explanation
 
-In the sample above, the class `DivideCases` does not implement `IEnumerable`.
+In the sample above, the class `DivideCases` does not implement `IEnumerable` nor `IAsyncEnumerable`
 
-However, source types specified by `TestCaseSource` [must implement `IEnumerable`](https://github.com/nunit/docs/wiki/TestCaseSource-Attribute).
+However, source types specified by `TestCaseSource` [must implement `IEnumerable` or `IAsyncEnumerable`](https://github.com/nunit/docs/wiki/TestCaseSource-Attribute).
 
 ### Fix
 
-Make the source type implement `IEnumerable`:
+Make the source type implement `IEnumerable` or `IAsyncEnumerable`
 
 ```csharp
 public class MyTestClass
@@ -84,7 +84,7 @@ Configure the severity per project, for more info see [MSDN](https://learn.micro
 ### Via .editorconfig file
 
 ```ini
-# NUnit1015: The source type does not implement IEnumerable
+# NUnit1015: The source type does not implement I(Async)Enumerable
 dotnet_diagnostic.NUnit1015.severity = chosenSeverity
 ```
 
@@ -93,22 +93,22 @@ where `chosenSeverity` can be one of `none`, `silent`, `suggestion`, `warning`,
 ### Via #pragma directive
 
 ```csharp
-#pragma warning disable NUnit1015 // The source type does not implement IEnumerable
+#pragma warning disable NUnit1015 // The source type does not implement I(Async)Enumerable
 Code violating the rule here
-#pragma warning restore NUnit1015 // The source type does not implement IEnumerable
+#pragma warning restore NUnit1015 // The source type does not implement I(Async)Enumerable
 ```
 
 Or put this at the top of the file to disable all instances.
 
 ```csharp
-#pragma warning disable NUnit1015 // The source type does not implement IEnumerable
+#pragma warning disable NUnit1015 // The source type does not implement I(Async)Enumerable
 ```
 
 ### Via attribute `[SuppressMessage]`
 
 ```csharp
 [System.Diagnostics.CodeAnalysis.SuppressMessage("Structure",
-    "NUnit1015:The source type does not implement IEnumerable",
+    "NUnit1015:The source type does not implement I(Async)Enumerable",
     Justification = "Reason...")]
 ```
 <!-- end generated config severity -->

documentation/NUnit1019.md

@@ -1,6 +1,6 @@
 # NUnit1019
 
-## The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable
+## The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 
 | Topic    | Value
 | :--      | :--
@@ -12,7 +12,7 @@
 
 ## Description
 
-The source specified by the TestCaseSource must return an IEnumerable or a type that implements IEnumerable.
+The source specified by the TestCaseSource must return an I(Async)Enumerable or a type that implements I(Async)Enumerable.
 
 ## Motivation
 
@@ -36,14 +36,14 @@ public class AnalyzeWhenSourceDoesProvideIEnumerable
 
 ### Explanation
 
-In the sample above, the source specified by `TestCaseSource` - the field `testCases` - does not return an `IEnumerable` or a type that implements `IEnumerable`,
+In the sample above, the source specified by `TestCaseSource` - the field `testCases` - does not return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`,
 instead it returns an `int`.
 
-However, sources specified by `TestCaseSource` [must return an `IEnumerable` or a type that implements `IEnumerable`.](https://github.com/nunit/docs/wiki/TestCaseSource-Attribute).
+However, sources specified by `TestCaseSource` [must return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`.](https://github.com/nunit/docs/wiki/TestCaseSource-Attribute).
 
 ### Fix
 
-Change `testCases` to return an `IEnumerable` or a type that implements `IEnumerable`:
+Change `testCases` to return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`:
 
 ```csharp
 public class AnalyzeWhenSourceDoesProvideIEnumerable
@@ -67,7 +67,7 @@ Configure the severity per project, for more info see [MSDN](https://learn.micro
 ### Via .editorconfig file
 
 ```ini
-# NUnit1019: The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable
+# NUnit1019: The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 dotnet_diagnostic.NUnit1019.severity = chosenSeverity
 ```
 
@@ -76,22 +76,22 @@ where `chosenSeverity` can be one of `none`, `silent`, `suggestion`, `warning`,
 ### Via #pragma directive
 
 ```csharp
-#pragma warning disable NUnit1019 // The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning disable NUnit1019 // The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 Code violating the rule here
-#pragma warning restore NUnit1019 // The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning restore NUnit1019 // The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 ```
 
 Or put this at the top of the file to disable all instances.
 
 ```csharp
-#pragma warning disable NUnit1019 // The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning disable NUnit1019 // The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 ```
 
 ### Via attribute `[SuppressMessage]`
 
 ```csharp
 [System.Diagnostics.CodeAnalysis.SuppressMessage("Structure",
-    "NUnit1019:The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable",
+    "NUnit1019:The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable",
     Justification = "Reason...")]
 ```
 <!-- end generated config severity -->

documentation/NUnit1024.md

@@ -1,6 +1,6 @@
 # NUnit1024
 
-## The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable
+## The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 
 | Topic    | Value
 | :--      | :--
@@ -12,7 +12,7 @@
 
 ## Description
 
-The source specified by the ValueSource must return an IEnumerable or a type that implements IEnumerable.
+The source specified by the ValueSource must return an I(Async)Enumerable or a type that implements I(Async)Enumerable.
 
 ## Motivation
 
@@ -36,14 +36,14 @@ public class AnalyzeWhenSourceDoesProvideIEnumerable
 
 ### Explanation
 
-In the sample above, the source specified by `ValueSource` - the field `testCases` - does not return an `IEnumerable` or a type that implements `IEnumerable`,
+In the sample above, the source specified by `ValueSource` - the field `testCases` - does not return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`,
 instead it returns an `int`.
 
-However, sources specified by `ValueSource` [must return an `IEnumerable` or a type that implements `IEnumerable`.](https://github.com/nunit/docs/wiki/ValueSource-Attribute).
+However, sources specified by `ValueSource` [must return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`.](https://github.com/nunit/docs/wiki/ValueSource-Attribute).
 
 ### Fix
 
-Change `testCases` to return an `IEnumerable` or a type that implements `IEnumerable`:
+Change `testCases` to return an `I(Async)Enumerable` or a type that implements `I(Async)Enumerable`:
 
 ```csharp
 public class AnalyzeWhenSourceDoesProvideIEnumerable
@@ -67,7 +67,7 @@ Configure the severity per project, for more info see [MSDN](https://learn.micro
 ### Via .editorconfig file
 
 ```ini
-# NUnit1024: The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable
+# NUnit1024: The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 dotnet_diagnostic.NUnit1024.severity = chosenSeverity
 ```
 
@@ -76,22 +76,22 @@ where `chosenSeverity` can be one of `none`, `silent`, `suggestion`, `warning`,
 ### Via #pragma directive
 
 ```csharp
-#pragma warning disable NUnit1024 // The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning disable NUnit1024 // The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 Code violating the rule here
-#pragma warning restore NUnit1024 // The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning restore NUnit1024 // The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 ```
 
 Or put this at the top of the file to disable all instances.
 
 ```csharp
-#pragma warning disable NUnit1024 // The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable
+#pragma warning disable NUnit1024 // The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable
 ```
 
 ### Via attribute `[SuppressMessage]`
 
 ```csharp
 [System.Diagnostics.CodeAnalysis.SuppressMessage("Structure",
-    "NUnit1024:The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable",
+    "NUnit1024:The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable",
     Justification = "Reason...")]
 ```
 <!-- end generated config severity -->

documentation/index.md

@@ -33,16 +33,16 @@ Rules which enforce structural requirements on the test code.
 | [NUnit1012](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1012.md) | The async test method must have a non-void return type | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1013](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1013.md) | The async test method must have a non-generic Task return type when no result is expected | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1014](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1014.md) | The async test method must have a Task\<T> return type when a result is expected | :white_check_mark: | :exclamation: | :x: |
-| [NUnit1015](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1015.md) | The source type does not implement IEnumerable | :white_check_mark: | :exclamation: | :x: |
+| [NUnit1015](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1015.md) | The source type does not implement I(Async)Enumerable | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1016](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1016.md) | The source type does not have a default constructor | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1017](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1017.md) | The specified source is not static | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1018](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1018.md) | The number of parameters provided by the TestCaseSource does not match the number of parameters in the target method | :white_check_mark: | :exclamation: | :x: |
-| [NUnit1019](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1019.md) | The source specified by the TestCaseSource does not return an IEnumerable or a type that implements IEnumerable | :white_check_mark: | :exclamation: | :x: |
+| [NUnit1019](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1019.md) | The source specified by the TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1020](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1020.md) | The TestCaseSource provides parameters to a source - field or property - that expects no parameters | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1021](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1021.md) | The ValueSource should use nameof operator to specify target | :white_check_mark: | :warning: | :white_check_mark: |
 | [NUnit1022](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1022.md) | The specified source is not static | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1023](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1023.md) | The target method expects parameters which cannot be supplied by the ValueSource | :white_check_mark: | :exclamation: | :x: |
-| [NUnit1024](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1024.md) | The source specified by the ValueSource does not return an IEnumerable or a type that implements IEnumerable | :white_check_mark: | :exclamation: | :x: |
+| [NUnit1024](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1024.md) | The source specified by the ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1025](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1025.md) | The ValueSource argument does not specify an existing member | :white_check_mark: | :exclamation: | :x: |
 | [NUnit1026](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1026.md) | The test or setup/teardown method is not public | :white_check_mark: | :exclamation: | :white_check_mark: |
 | [NUnit1027](https://github.com/nunit/nunit.analyzers/tree/master/documentation/NUnit1027.md) | The test method has parameters, but no arguments are supplied by attributes | :white_check_mark: | :exclamation: | :x: |

src/nunit.analyzers.tests/TestCaseSourceUsage/TestCaseSourceSourceTypeTests.cs

@@ -1,4 +1,7 @@
+using System.Collections.Generic;
+using System.Linq;
 using Gu.Roslyn.Asserts;
+using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Diagnostics;
 using NUnit.Analyzers.Constants;
 using NUnit.Analyzers.TestCaseSourceUsage;
@@ -51,10 +54,37 @@ class MyTests
 
             var expectedDiagnostic = ExpectedDiagnostic
                 .Create(AnalyzerIdentifiers.TestCaseSourceSourceTypeNotIEnumerable)
-                .WithMessage("The source type 'MyTests' does not implement IEnumerable");
+                .WithMessage("The source type 'MyTests' does not implement I(Async)Enumerable");
             RoslynAssert.Diagnostics(analyzer, expectedDiagnostic, testCode);
         }
 
+        [Test]
+        public void AnalyzeWhenTypeOfSourceImplementsIAsyncEnumerable()
+        {
+            var testCode = TestUtility.WrapClassInNamespaceAndAddUsing(@"
+    public class AnalyzeWhenTypeOfSourceImplementsIAsyncEnumerable
+    {
+        [TestCaseSource(typeof(MyTests))]
+        public void Test(int i)
+        {
+        }
+    }
+
+    public sealed class MyTests : IAsyncEnumerable<int>
+    {
+        public IAsyncEnumerator<int> GetAsyncEnumerator(CancellationToken cancellationToken = default(CancellationToken))
+        {
+            throw new NotImplementedException();
+        }
+    }",
+        additionalUsings: "using System.Collections.Generic;using System.Threading;");
+
+            IEnumerable<MetadataReference> asyncEnumerableMetadata = MetadataReferences.Transitive(typeof(IAsyncEnumerable<>));
+            IEnumerable<MetadataReference> metadataReferences = (Settings.Default.MetadataReferences ?? Enumerable.Empty<MetadataReference>()).Concat(asyncEnumerableMetadata);
+
+            RoslynAssert.Valid(analyzer, testCode, Settings.Default.WithMetadataReferences(metadataReferences));
+        }
+
         [Test]
         public void AnalyzeWhenTypeOfSourceNoDefaultConstructor()
         {

src/nunit.analyzers.tests/TestCaseSourceUsage/TestCaseSourceUsesStringAnalyzerTests.cs

@@ -322,7 +322,7 @@ public void Test()
 
             var expectedDiagnostic = ExpectedDiagnostic
                 .Create(AnalyzerIdentifiers.TestCaseSourceDoesNotReturnIEnumerable)
-                .WithMessage($"The TestCaseSource does not return an IEnumerable or a type that implements IEnumerable. Instead it returns a '{returnType}'.");
+                .WithMessage($"The TestCaseSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable. Instead it returns a '{returnType}'.");
             RoslynAssert.Diagnostics(analyzer, expectedDiagnostic, testCode);
         }
 

src/nunit.analyzers.tests/ValueSourceUsage/ValueSourceUsageAnalyzerTests.cs

@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System.Linq;
 using Gu.Roslyn.Asserts;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CodeFixes;
@@ -199,7 +201,8 @@ public static IEnumerable<int> TestData(string dummy, int anotherDummy)
         [TestCase("private static TestCaseData[] TestCases => new TestCaseData[0];")]
         [TestCase("private static TestCaseData[] TestCases() => new TestCaseData[0];")]
         [TestCase("private static Task<TestCaseData[]> TestCases() => Task.FromResult(new TestCaseData[0]);")]
-        public void AnalyzeWhenSourceDoesProvideIEnumerable(string testCaseMember)
+        [TestCase("private static async IAsyncEnumerable<int> TestCases() { foreach (var value in new[] { 0 }) { yield return value; await Task.Yield(); } }", "using System.Collections.Generic;")]
+        public void AnalyzeWhenSourceDoesProvideIEnumerable(string testCaseMember, string? additionalUsings = null)
         {
             var testCode = TestUtility.WrapClassInNamespaceAndAddUsing($@"
     public class AnalyzeWhenSourceDoesProvideIEnumerable
@@ -210,9 +213,12 @@ public class AnalyzeWhenSourceDoesProvideIEnumerable
         public void Test([ValueSource(nameof(TestCases))] int number)
         {{
         }}
-    }}");
+    }}", additionalUsings);
 
-            RoslynAssert.Valid(analyzer, testCode);
+            IEnumerable<MetadataReference> asyncEnumerableMetadata = MetadataReferences.Transitive(typeof(IAsyncEnumerable<>));
+            IEnumerable<MetadataReference> metadataReferences = (Settings.Default.MetadataReferences ?? Enumerable.Empty<MetadataReference>()).Concat(asyncEnumerableMetadata);
+
+            RoslynAssert.Valid(analyzer, testCode, Settings.Default.WithMetadataReferences(metadataReferences));
         }
 
         [TestCase("private static readonly object? TestCases = null;", "object?")]
@@ -230,7 +236,7 @@ public void Test([ValueSource(nameof(TestCases))] int number)
         public void AnalyzeWhenSourceDoesNotProvideIEnumerable(string testCaseMember, string returnType)
         {
             var testCode = TestUtility.WrapClassInNamespaceAndAddUsing($@"
-    public class AnalyzeWhenSourceDoesProvideIEnumerable
+    public class AnalyzeWhenSourceDoesNotProvideIEnumerable
     {{
 #pragma warning disable CS0414 // Consider changing the field to a 'const'
         {testCaseMember}
@@ -244,7 +250,7 @@ public void Test([ValueSource(nameof(TestCases))] int number)
 
             var expectedDiagnostic = ExpectedDiagnostic
                 .Create(AnalyzerIdentifiers.ValueSourceDoesNotReturnIEnumerable)
-                .WithMessage($"The ValueSource does not return an IEnumerable or a type that implements IEnumerable. Instead it returns a '{returnType}'.");
+                .WithMessage($"The ValueSource does not return an I(Async)Enumerable or a type that implements I(Async)Enumerable. Instead it returns a '{returnType}'.");
             RoslynAssert.Diagnostics(analyzer, expectedDiagnostic, testCode);
         }