Move VSMEF005 no-warning test to NoWarningTests; update copilot instructions

Author: AArnott

.github/copilot-instructions.md

@@ -2,71 +2,82 @@
 
 ## High level guidance
 
-* Review the `CONTRIBUTING.md` file for instructions to build and test the software.
-* Set the `NBGV_GitEngine` environment variable to `Disabled` before running any `dotnet` or `msbuild` commands.
+- Review the `CONTRIBUTING.md` file for instructions to build and test the software.
+- Set the `NBGV_GitEngine` environment variable to `Disabled` before running any `dotnet` or `msbuild` commands.
 
 ## Software Design
 
-* Design APIs to be highly testable, and all functionality should be tested.
-* Avoid introducing binary breaking changes in public APIs of projects under `src` unless their project files have `IsPackable` set to `false`.
+- Design APIs to be highly testable, and all functionality should be tested.
+- Avoid introducing binary breaking changes in public APIs of projects under `src` unless their project files have `IsPackable` set to `false`.
 
 ## Testing
 
 **IMPORTANT**: This repository uses Microsoft.Testing.Platform (MTP v2) with xunit v3. Traditional `--filter` syntax does NOT work. Use the options below instead.
 
-* There should generally be one test project (under the `test` directory) per shipping project (under the `src` directory). Test projects are named after the project being tested with a `.Tests` suffix.
-* Tests use xunit v3 with Microsoft.Testing.Platform (MTP v2). Traditional VSTest `--filter` syntax does NOT work.
-* Some tests are known to be unstable. When running tests, you should skip the unstable ones by using `-- --filter-not-trait "FailsInCloudTest=true"`.
+- There should generally be one test project (under the `test` directory) per shipping project (under the `src` directory). Test projects are named after the project being tested with a `.Tests` suffix.
+- Analyzer tests that validate _no_ diagnostics are emitted should go in `test/Microsoft.VisualStudio.Composition.Analyzers.Tests/MultiAnalyzerTests.cs`, which runs all analyzers simultaneously. Tests for specific diagnostics being emitted go in the per-analyzer test files. Add any new analyzer to the list in `test/Microsoft.VisualStudio.Composition.Analyzers.Tests/Helpers/CSharpMultiAnalyzerVerifier+Test.cs`.
+- Tests use xunit v3 with Microsoft.Testing.Platform (MTP v2). Traditional VSTest `--filter` syntax does NOT work.
+- Some tests are known to be unstable. When running tests, you should skip the unstable ones by using `-- --filter-not-trait "FailsInCloudTest=true"`.
 
 ### Running Tests
 
 **Run all tests**:
+
 ```bash
 dotnet test --no-build -c Release
 ```
 
 **Run tests for a specific test project**:
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release
 ```
 
 **Run a single test method**:
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-method ClassName.MethodName
 ```
 
 **Run all tests in a test class**:
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-class ClassName
 ```
 
 **Run tests with wildcard matching** (supports wildcards at beginning and/or end):
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-method "*Pattern*"
 ```
 
 **Run tests with a specific trait** (equivalent to category filtering):
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-trait "TraitName=value"
 ```
 
 **Exclude tests with a specific trait** (skip unstable tests):
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release -- --filter-not-trait "TestCategory=FailsInCloudTest"
 ```
 
 **Run tests for a specific framework only**:
+
 ```bash
 dotnet test --project test/Library.Tests/Library.Tests.csproj --no-build -c Release --framework net9.0
 ```
 
 **List all available tests without running them**:
+
 ```bash
 cd test/Library.Tests
 dotnet run --no-build -c Release --framework net9.0 -- --list-tests
 ```
 
 **Key points about test filtering with MTP v2 / xunit v3**:
+
 - Options after `--` are passed to the test runner, not to `dotnet test`
 - Use `--filter-method`, `--filter-class`, `--filter-namespace` for simple filtering
 - Use `--filter-trait` and `--filter-not-trait` for trait-based filtering (replaces `--filter "TestCategory=..."`)
@@ -77,6 +88,6 @@ dotnet run --no-build -c Release --framework net9.0 -- --list-tests
 
 ## Coding style
 
-* Honor StyleCop rules and fix any reported build warnings *after* getting tests to pass.
-* In C# files, use namespace *statements* instead of namespace *blocks* for all new files.
-* Add API doc comments to all new public and internal members.
+- Honor StyleCop rules and fix any reported build warnings _after_ getting tests to pass.
+- In C# files, use namespace _statements_ instead of namespace _blocks_ for all new files.
+- Add API doc comments to all new public and internal members.

…sition.Analyzers.Tests/NoWarningTests.cs …on.Analyzers.Tests/MultiAnalyzerTests.cstest/Microsoft.VisualStudio.Composition.Analyzers.Tests/NoWarningTests.cs renamed to test/Microsoft.VisualStudio.Composition.Analyzers.Tests/MultiAnalyzerTests.cs test/Microsoft.VisualStudio.Composition.Analyzers.Tests/NoWarningTests.cs renamed to test/Microsoft.VisualStudio.Composition.Analyzers.Tests/MultiAnalyzerTests.cs

@@ -7,7 +7,7 @@
 /// These tests verify that valid code does not trigger any analyzer diagnostics.
 /// Each test verifies the source code against all VSMEF analyzers simultaneously.
 /// </summary>
-public class NoWarningTests
+public class MultiAnalyzerTests
 {
     [Fact]
     public async Task ClassWithNoConstructors_NoWarning()
@@ -41,6 +41,22 @@ public Foo(string value) { }
         await VerifyAll.VerifyAnalyzerAsync(test);
     }
 
+    [Fact]
+    public async Task ClassWithSingleDefaultConstructor_NoWarning()
+    {
+        string test = """
+            using System.ComponentModel.Composition;
+
+            [Export]
+            class Foo
+            {
+                public Foo() { }
+            }
+            """;
+
+        await VerifyAll.VerifyAnalyzerAsync(test);
+    }
+
     [Fact]
     public async Task ClassWithMultipleNonImportingConstructors_NoWarning()
     {

test/Microsoft.VisualStudio.Composition.Analyzers.Tests/VSMEF005MultipleImportingConstructorsAnalyzerTests.cs

@@ -5,22 +5,6 @@
 
 public class VSMEF005MultipleImportingConstructorsAnalyzerTests
 {
-    [Fact]
-    public async Task ClassWithSingleNonImportingConstructor_NoWarning()
-    {
-        string test = """
-            using System.ComponentModel.Composition;
-
-            [Export]
-            class Foo
-            {
-                public Foo(string value) { }
-            }
-            """;
-
-        await VerifyCS.VerifyAnalyzerAsync(test);
-    }
-
     [Fact]
     public async Task ClassWithMultipleImportingConstructors_Warning()
     {