Skip to content

Fix log accumulation across DynamicData test invocations #7925

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Evangelink merged 3 commits into from
Apr 29, 2026
Merged

Fix log accumulation across DynamicData test invocations #7925

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
4795ceb
Fix log accumulation across DynamicData test invocations
Evangelink Apr 29, 2026
e75d99f
Make GetAndClear atomic on SynchronizedStringBuilder
Evangelink Apr 29, 2026
06de037
Address review feedback: improve test coverage
Evangelink Apr 29, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
18 changes: 9 additions & 9 deletions src/Adapter/MSTestAdapter.PlatformServices/Execution/TestClassInfo.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -458,9 +458,9 @@ async Task<TestResult> DoRunAsync()
{
// Assembly initialize and class initialize logs are pre-pended to the first result.
var testContextImpl = testContext as TestContextImplementation;
result.LogOutput = initializationLogs + testContextImpl?.GetOut();
result.LogError = initializationErrorLogs + testContextImpl?.GetErr();
result.DebugTrace = initializationTrace + testContextImpl?.GetTrace();
result.LogOutput = initializationLogs + testContextImpl?.GetAndClearOutput();
result.LogError = initializationErrorLogs + testContextImpl?.GetAndClearError();
result.DebugTrace = initializationTrace + testContextImpl?.GetAndClearTrace();
result.TestContextMessages = initializationTestContextMessages + testContext.GetAndClearDiagnosticMessages();
}

Expand Down Expand Up @@ -680,19 +680,19 @@ async Task<TestResult> DoRunAsync()
Outcome = UnitTestOutcome.Failed,
DisplayName = $"[{ClassType.FullName} ClassCleanup]",
TestFailureException = ex,
LogOutput = testContextImpl?.GetOut(),
LogError = testContextImpl?.GetErr(),
DebugTrace = testContextImpl?.GetTrace(),
LogOutput = testContextImpl?.GetAndClearOutput(),
LogError = testContextImpl?.GetAndClearError(),
DebugTrace = testContextImpl?.GetAndClearTrace(),
TestContextMessages = testContext.GetAndClearDiagnosticMessages(),
};
}

if (results.Length > 0)
{
TestResult lastResult = results[results.Length - 1];
lastResult.LogOutput += testContextImpl?.GetOut();
lastResult.LogError += testContextImpl?.GetErr();
lastResult.DebugTrace += testContextImpl?.GetTrace();
lastResult.LogOutput += testContextImpl?.GetAndClearOutput();
lastResult.LogError += testContextImpl?.GetAndClearError();
lastResult.DebugTrace += testContextImpl?.GetAndClearTrace();
lastResult.TestContextMessages += testContext.GetAndClearDiagnosticMessages();
}

Expand Down
6 changes: 3 additions & 3 deletions src/Adapter/MSTestAdapter.PlatformServices/Execution/TestMethodInfo.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -148,9 +148,9 @@ public virtual async Task<TestResult> InvokeAsync(object?[]? arguments)
if (result != null)
{
var testContextImpl = TestContext as TestContextImplementation;
result.LogOutput = testContextImpl?.GetOut();
result.LogError = testContextImpl?.GetErr();
result.DebugTrace = testContextImpl?.GetTrace();
result.LogOutput = testContextImpl?.GetAndClearOutput();
result.LogError = testContextImpl?.GetAndClearError();
result.DebugTrace = testContextImpl?.GetAndClearTrace();
result.TestContextMessages = TestContext?.GetAndClearDiagnosticMessages();
result.ResultFiles = TestContext?.GetResultFiles();
result.Duration = watch.Elapsed;
Expand Down
18 changes: 9 additions & 9 deletions src/Adapter/MSTestAdapter.PlatformServices/Execution/UnitTestRunner.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -265,9 +265,9 @@ private static async Task<TestResult> RunAssemblyInitializeIfNeededAsync(TestMet
finally
{
var testContextImpl = testContext.Context as TestContextImplementation;
result!.LogOutput = testContextImpl?.GetOut();
result.LogError = testContextImpl?.GetErr();
result.DebugTrace = testContextImpl?.GetTrace();
result!.LogOutput = testContextImpl?.GetAndClearOutput();
result.LogError = testContextImpl?.GetAndClearError();
result.DebugTrace = testContextImpl?.GetAndClearTrace();
result.TestContextMessages = testContext.GetAndClearDiagnosticMessages();
}

Expand All @@ -288,19 +288,19 @@ private static async Task<TestResult> RunAssemblyInitializeIfNeededAsync(TestMet
{
Outcome = UnitTestOutcome.Failed,
TestFailureException = ex,
LogOutput = testContextImpl?.GetOut(),
LogError = testContextImpl?.GetErr(),
DebugTrace = testContextImpl?.GetTrace(),
LogOutput = testContextImpl?.GetAndClearOutput(),
LogError = testContextImpl?.GetAndClearError(),
DebugTrace = testContextImpl?.GetAndClearTrace(),
TestContextMessages = testContext.GetAndClearDiagnosticMessages(),
};
}

if (results.Length > 0)
{
TestResult lastResult = results[results.Length - 1];
lastResult.LogOutput += testContextImpl?.GetOut();
lastResult.LogError += testContextImpl?.GetErr();
lastResult.DebugTrace += testContextImpl?.GetTrace();
lastResult.LogOutput += testContextImpl?.GetAndClearOutput();
lastResult.LogError += testContextImpl?.GetAndClearError();
lastResult.DebugTrace += testContextImpl?.GetAndClearTrace();
lastResult.TestContextMessages += testContext.GetAndClearDiagnosticMessages();
}
}
Expand Down
21 changes: 15 additions & 6 deletions src/Adapter/MSTestAdapter.PlatformServices/Services/TestContextImplementation.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,15 @@ internal void AppendLine(string? value)
internal void Clear()
=> _builder.Clear();

[MethodImpl(MethodImplOptions.Synchronized)]
internal string GetAndClear()
{
string result = _builder.ToString();
_builder.Clear();

return result;
}

[MethodImpl(MethodImplOptions.Synchronized)]
public override string ToString()
=> _builder.ToString();
Expand Down Expand Up @@ -380,12 +389,12 @@ private SynchronizedStringBuilder GetTestContextMessagesStringBuilder()
return _testContextMessageStringBuilder;
}

internal string? GetOut()
=> _stdOutStringBuilder?.ToString();
internal string? GetAndClearOutput()
=> _stdOutStringBuilder?.GetAndClear();

internal string? GetErr()
=> _stdErrStringBuilder?.ToString();
internal string? GetAndClearError()
=> _stdErrStringBuilder?.GetAndClear();

internal string? GetTrace()
=> _traceStringBuilder?.ToString();
internal string? GetAndClearTrace()
=> _traceStringBuilder?.GetAndClear();
}
39 changes: 39 additions & 0 deletions test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/Execution/TestMethodInfoTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1501,6 +1501,45 @@ public void ResolveArgumentsShouldReturnPopulatedParamsWithAllProvided()
((string[])expectedArguments[1]).SequenceEqual((string[])resolvedArguments[1]!).Should().BeTrue();
}

// Regression tests for https://github.com/microsoft/testfx/issues/7846
// Verify that log output buffers are cleared between invocations to prevent
// exponential memory growth with DynamicData tests.
// NOTE: The TestClassInfo (class init/cleanup) and UnitTestRunner (assembly init/cleanup)
// call sites use the same GetAndClear* methods tested in isolation in
// TestContextImplementationTests.GetAndClear{Output,Error,Trace}_ShouldReturnContentThenClearBuffer.
public async Task InvokeAsync_ShouldNotAccumulateLogOutputAcrossMultipleInvocations()
{
DummyTestClass.TestMethodBody = _ => _testContextImplementation.WriteConsoleOut("invocation_output");

TestResult result1 = await _testMethodInfo.InvokeAsync(null);
TestResult result2 = await _testMethodInfo.InvokeAsync(null);

result1.LogOutput.Should().Be("invocation_output");
result2.LogOutput.Should().Be("invocation_output");
}

public async Task InvokeAsync_ShouldNotAccumulateLogErrorAcrossMultipleInvocations()
{
DummyTestClass.TestMethodBody = _ => _testContextImplementation.WriteConsoleErr("error_output");

TestResult result1 = await _testMethodInfo.InvokeAsync(null);
TestResult result2 = await _testMethodInfo.InvokeAsync(null);

result1.LogError.Should().Be("error_output");
result2.LogError.Should().Be("error_output");
}

public async Task InvokeAsync_ShouldNotAccumulateDebugTraceAcrossMultipleInvocations()
{
DummyTestClass.TestMethodBody = _ => _testContextImplementation.WriteTrace("trace_output");

TestResult result1 = await _testMethodInfo.InvokeAsync(null);
TestResult result2 = await _testMethodInfo.InvokeAsync(null);

result1.DebugTrace.Should().Be("trace_output");
result2.DebugTrace.Should().Be("trace_output");
}
Comment thread
Evangelink marked this conversation as resolved.

#region helper methods

private static async Task RunWithTestablePlatformService(TestablePlatformServiceProvider testablePlatformServiceProvider, Func<Task> action)
Expand Down
41 changes: 39 additions & 2 deletions ...Tests/MSTestAdapter.PlatformServices.UnitTests/Services/TestContextImplementationTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -347,6 +347,42 @@ public void DisplayMessageShouldForwardToIMessageLogger()
messageLoggerMock.Verify(x => x.SendMessage(TestMessageLevel.Error, "ErrorMessage"), Times.Once);
}

public void GetAndClearOutput_ShouldReturnContentThenClearBuffer()
{
_testContextImplementation = CreateTestContextImplementation();
_testContextImplementation.WriteConsoleOut("hello");

string? first = _testContextImplementation.GetAndClearOutput();
string? second = _testContextImplementation.GetAndClearOutput();

first.Should().Be("hello");
second.Should().BeEmpty();
}

public void GetAndClearError_ShouldReturnContentThenClearBuffer()
{
_testContextImplementation = CreateTestContextImplementation();
_testContextImplementation.WriteConsoleErr("hello");

string? first = _testContextImplementation.GetAndClearError();
string? second = _testContextImplementation.GetAndClearError();

first.Should().Be("hello");
second.Should().BeEmpty();
}

public void GetAndClearTrace_ShouldReturnContentThenClearBuffer()
{
_testContextImplementation = CreateTestContextImplementation();
_testContextImplementation.WriteTrace("hello");

string? first = _testContextImplementation.GetAndClearTrace();
string? second = _testContextImplementation.GetAndClearTrace();

first.Should().Be("hello");
second.Should().BeEmpty();
}

public void WritesFromBackgroundThreadShouldNotThrow()
{
TestContextImplementation testContextImplementation = CreateTestContextImplementation(new Mock<IMessageLogger>().Object);
Expand All @@ -360,8 +396,9 @@ public void WritesFromBackgroundThreadShouldNotThrow()
});

t.Start();
_ = testContextImplementation.GetOut();
_ = testContextImplementation.GetErr();
_ = testContextImplementation.GetAndClearOutput();
_ = testContextImplementation.GetAndClearError();
_ = testContextImplementation.GetAndClearTrace();
t.Join();
}
}
Comment thread
Evangelink marked this conversation as resolved.
Comment thread
Evangelink marked this conversation as resolved.
Loading