I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

Tagging subscribers to this area: @tommcdon
See info in area-owners.md if you want to be subscribed.

@danmoseley Are tests for debugger displays required?

@danmoseley Are tests for debugger displays required?

yes, I've seen cases where a debugger display threw an exception, like any code. In fact, that's a good reason to put it in a private property like this, so it's easier to test.

@I-SER-I perhaps you could add a simple test that creates a Stopwatch, verifies (through reflection) that its DebuggerDisplay property string matches $"{sw.Elapsed} (IsRunning = {sw.IsRunning})", and maybe again with it started?

verifies (through reflection)

@danmoseley, Could you help me where I need to implement DebuggerDisplayTest?
Because I didn't find a StopwatchTest

@danmoseley, Could you help me where I need to implement DebuggerDisplayTest? Because I didn't find a StopwatchTest

@stephentoub )

@I-SER-I
I think you have to create a new test class in src/libraries/System.Runtime/tests with a test validating the result of the DebuggerDisplay.

Not sure how I didn't see the notification. Anyway, yes, what @deeprobin said. The reason the tests go there is that System.Runtime is where the type is exposed (https://github.com/dotnet/runtime/blob/4225cb0fff263e9fbc7ad007ab18e774a1b73d1e/src/libraries/System.Runtime/ref/System.Runtime.cs#L7345)

I'll add the test.

@steveisok any idea what's going on iwth the mono minjit lane?

The test has passed across wasm, devices, all OS, AOT... I think the failure of the whole minijit lane does not materially affect coverage.