MSTest v4 Breaking Changes

[Evangelink]

Description

The goal of this ticket is to announce the upcoming breaking changes in MSTest v4.

Planned

• Convert MSTest to async pattern (Convert MSTest to async pattern #1284)
• Caller argument expression (Openness for Caller Argument Expression in Assert failure messages #1154)
• Disable appdomain usage by default (Disable appdomain usage by default #1297)
• Change ClassCleanup default behavior to be "EndOfClass" (Change ClassCleanup default behavior to be "EndOfClass" #1316)
• Remove ClassCleanupBehavior.EndOfAssembly (Remove ClassCleanupBehavior.EndOfAssembly #1574)
• Drop TestTimeout enum and related overload on TimeoutAttribute (Drop TestTimeout enum and related overload on TimeoutAttribute #1317)
• Update TestContext.Properties return type to IDictionary<string, object> (Update TestContext.Properties return type to IDictionary<string, object> #1377)
• Remove deprecated BeginTimer and EndTimer methods (Remove deprecated BeginTimer and EndTimer methods #1454)
• Deprecate TestContext properties kept for compatibility (Deprecate TestContext properties kept for compatibility #1453)
• Better DisplayName for data tests (Better DisplayNames for DataSource tests #713)
• Unify SetOutcome behavior across all target frameworks (TestContext: Unify SetOutcome behavior across TFMs #1426)
• Deprecate ExpectedExceptionAttribute (Deprecate ExpectedException attribute. #135)
• Simpify assembly names to improve 260 chars limitation (Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices errors due to path length not handled well on UWP #1607)
• Disable CaptureTraceOutput by default (linked issue TraceListenerManager is not thread safe #2616)
• [v4] Broader changes for the story around attributes and their inheritance #4292

To be discussed

• Reintroduce tree structure (InnerResults) for parameterized tests (Data Driven tests - Individual results of data rows are not in tree structure, missing parentID in trx file #1024)
• Use a better serialization/deserialization mechanism for data discovery (Use a better serialization/deserialization mechanism for data discovery #1462)
• DataRow: Nulls and empty string are displayed as no data in display name (DataRow: Nulls and empty string are displayed as no data in display name #1647)

[Nirmal4G]

I also propose a new Shared Framework of testing tools and frameworks in .NET SDK along with a new Test SDK for the Project (not just a simple rename as requested in #2693). May be not for v4 but for v5 maybe? .NET 10? Basically, a built-in Testing support from the .NET SDK without any external dependencies.

See #3254 for the proposal and discussion.