Add Assert.Scope() for soft assertions

[Evangelink]

Fixes #571

[Copilot]

Pull request overview

This pull request implements soft assertions through a new Assert.Scope() API that allows multiple assertion failures to be collected and reported together, addressing issue #571. When using Assert.Scope(), assertions failures are collected instead of thrown immediately, and all collected failures are reported when the scope is disposed.

Changes:

• Adds Assert.Scope() experimental API for soft assertion collection
• Refactors assertion failure reporting: introduces ReportAssertFailed for soft assertions while keeping ThrowAssertFailed for hard assertions (Assert.Fail, Assert.Inconclusive)
• Updates all assertion methods to use ReportAssertFailed except for hard assertions and parameter validation
• Includes comprehensive RFC documentation explaining design decisions around nullability annotations and postconditions

Reviewed changes

Copilot reviewed 40 out of 40 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/TestFramework/TestFramework/Assertions/AssertScope.cs	Core implementation of assertion scope using AsyncLocal and ConcurrentQueue for thread-safe failure collection
src/TestFramework/TestFramework/Assertions/Assert.Scope.cs	Public API for Assert.Scope() marked as experimental
src/TestFramework/TestFramework/Assertions/Assert.cs	Adds ReportAssertFailed method with soft assertion support and refactors message formatting
src/TestFramework/TestFramework/Assertions/Assert.*.cs	Updates all assertion classes (AreEqual, IsTrue, IsNull, etc.) to use ReportAssertFailed
src/TestFramework/TestFramework/Assertions/StringAssert.cs	Updates string assertions to use ReportAssertFailed
src/TestFramework/TestFramework/Assertions/CollectionAssert.cs	Updates collection assertions to use ReportAssertFailed
src/TestFramework/TestFramework/Resources/FrameworkMessages.resx	Adds new messages for scope failures, removes AssertThatFailedFormat, updates AssertionFailed format
src/TestFramework/TestFramework/Resources/xlf/*.xlf	Updates all localization files with new strings marked as needing translation
src/TestFramework/TestFramework/PublicAPI/PublicAPI.Unshipped.txt	Adds Assert.Scope() to public API
test/UnitTests/TestFramework.UnitTests/Assertions/AssertTests.ScopeTests.cs	Comprehensive test coverage for Assert.Scope() functionality
test/UnitTests/TestFramework.UnitTests/Assertions/AssertTests.That.cs	Updates test expectations for Assert.That message format changes
test/UnitTests/TestFramework.UnitTests/Assertions/AssertTests.ThrowsExceptionTests.cs	Renames test to match ReportAssertFailed
docs/RFCs/011-Soft-Assertions-Nullability-Design.md	Detailed RFC documenting design decisions, nullability annotation handling, and trade-offs

[Youssef1313]

Approved. But I would love to see a full E2E test

[Copilot]

Pull request overview

Copilot reviewed 41 out of 41 changed files in this pull request and generated 4 comments.

Comments suppressed due to low confidence (1)

src/TestFramework/TestFramework/Assertions/Assert.cs:235

• CheckParameterNotNull now throws via CreateAssertFailedException directly. This bypasses LaunchDebuggerIfNeeded() and also loses the [StackTraceHidden] behavior provided by ThrowAssertFailed, so null-parameter failures will behave differently from other assertion failures. Consider routing this through ThrowAssertFailed(assertionName, finalMessage) (or otherwise ensuring debugger-launch + stacktrace-hiding parity).

    internal static void CheckParameterNotNull([NotNull] object? param, string assertionName, string parameterName)
    {
        if (param is null)
        {
            string finalMessage = string.Format(CultureInfo.CurrentCulture, FrameworkMessages.NullParameterToAssert, parameterName);
            throw CreateAssertFailedException(assertionName, finalMessage);
        }

[Copilot]

Copilot's findings

• Files reviewed: 41/41 changed files
• Comments generated: 2