Enhance MSTEST0037 to suggest Assert.IsNotEmpty for collection count patterns

[Copilot]

The MSTEST0037 analyzer now detects collection emptiness patterns and suggests Assert.IsNotEmpty instead of generic comparison/equality assertions for better readability and intent clarity.

Changes Made

Before this change:

Assert.IsTrue(myList.Count > 0);  // Suggested: Assert.IsGreaterThan(0, myList.Count)
Assert.IsTrue(myList.Count != 0); // Suggested: Assert.AreNotEqual(0, myList.Count)

After this change:

Assert.IsTrue(myList.Count > 0);  // Now suggests: Assert.IsNotEmpty(myList)
Assert.IsTrue(myList.Count != 0); // Now suggests: Assert.IsNotEmpty(myList)

Implementation Details

• Added RecognizeCollectionEmptinessCheck method to detect collection count/length patterns with zero
• Supports both Count and Length properties on BCL collection types (List, arrays, etc.)
• Handles reverse order patterns like 0 != myList.Count
• Only applies to Assert.IsTrue() calls to maintain semantic correctness
• Uses existing CodeFixModeSimple for seamless integration with the codefix
• Prioritizes collection-specific suggestions before generic comparison logic

Comprehensive Coverage

The analyzer now handles these patterns:

• myCollection.Count > 0 → Assert.IsNotEmpty(myCollection)
• myCollection.Count != 0 → Assert.IsNotEmpty(myCollection)
• myArray.Length > 0 → Assert.IsNotEmpty(myArray)
• myArray.Length != 0 → Assert.IsNotEmpty(myArray)
• 0 != myCollection.Count → Assert.IsNotEmpty(myCollection) (reverse order)

While preserving existing behavior for:

• myCollection.Count > 2 → Assert.IsGreaterThan(2, myCollection.Count)
• myCollection.Count != 5 → Assert.AreNotEqual(5, myCollection.Count)
• Assert.AreEqual(0, myCollection.Count) → Assert.IsEmpty(myCollection)

Testing

Added comprehensive test coverage including:

• Generic collections (List<T>)
• Arrays (T[])
• Reverse order patterns
• Edge cases to ensure no regression
• Non-BCL collections (correctly fall back to generic suggestions)

Fixes #6312.

Warning

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I tried to connect to the following addresses, but was blocked by firewall rules:

• 4m6vsblobprodcus384.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• 4zjvsblobprodcus390.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• 6s7vsblobprodcus313.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• ckzvsblobprodcus347.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• l49vsblobprodcus358.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• m16vsblobprodcus374.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• pe3vsblobprodcus354.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)
• ytvvsblobprodcus310.vsblob.vsassets.io
  • Triggering command: dotnet build src/Analyzers/MSTest.Analyzers/MSTest.Analyzers.csproj --verbosity quiet (dns block)
  • Triggering command: dotnet test test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj --filter ClassName=UseProperAssertMethodsAnalyzerTests --verbosity minimal --no-restore --no-build (dns block)

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