DragDrop unit tests hang, should be integration tests

[weltkante]

.NET Core Version:
master

Have you experienced this same bug with .NET Framework?:
not applicable

Problem description:
DoDragDrop tests in ToolStripItemTests and ControlTests are hanging CI.

Not sure if its worth to root-cause the hang, I think they should be integration tests instead as proper drag'n'drop tests need mouse interaction, otherwise OLE probably exits out very early. These tests basically just cover a failure case which in practice nobody is interested in (and can easily be covered by the integration test as well). Sure, its useful to ensure that a noop failure case stays a noop failure case, but it may give a false sense of test coverage if there is actually no test of the code paths used for successful drag'n'drop.

Expected behavior:

• DoDragDrop tests should not hang CI
• DoDragDrop tests should cover non-failure-cases (requires integration test)

Minimal repro:

• run the tests with xunit.stafact updated to 1.0.33 or unskip them from PR update Xunit.StaFact to include bugfixes #3276

[hughbe]

I did add these tests to make sure our interop bindings worked (i.e. didn't crash, throw EntryPointNotFoundException etc)

[willibrandon]

If the intent is to test interop bindings work and do not crash, perhaps the new integration tests in DragDropTests will suffice?

[weltkante]

Probably, since any test that covers a working scenario implicitly also covers testing whether the interop definitions work. I don't know if the original tests still show up as hangs, if so its probably worth removing them if we now have tests that do the same and more.