ATL ActiveX control with unit test

[weltkante]

Contributes to #8294 and #8302

This is WIP and an early draft to get feedback. Open questions are:

• where to put the controls? where to put the unit tests?
• For the draft I put the control in the existing CMake "NativeTests" file and the tests along the other AxHost tests, however if that is the right place then the unit test project either needs the manifest reference added or an activation context needs to load the manifest dynamically.
• is it ok to pull in the ATL headers into the NativeTests project? its awkward to not have a shared header (even if its not using the "precompiled header" feature), the way the individual headers pull in different platform headers in different orders (e.g. windows.h) means different cpp files see different configurations of the headers
• currently only contains an ATL control, it might also be desireable to add an MFC control (which uses a different infrastructure and implementation on the C++ side but otherwise would be implemented similarly on the C# unit test side)

/cc @JeremyKuhne for comments and suggestions

Proposed changes

• add ATL ActiveX control
  • test for control creation
  • test for event handling
• [TODO] add MFC ActiveX control, if desired?
• [TODO] variations of the tests using source generated interfaces instead of classic COM interop (might do that in a different PR)

Customer Impact

• none, only increases test coverage

Regression?

• No

Risk

• none, only unit tests are changed

Before

• lacking unit tests of ATL/MFC ActiveX controls

After

• add unit tests for ATL/MFC ActiveX controls hosted via AxHost

Test methodology

• automated tests

Accessibility testing

• not included (accessibility is not customized on native side and retains default behavior)

Test environment(s)

• 9.0.0-preview.2.24077.1 (whatever is pulled in by the build.cmd/start-vs.cmd on current main branch)

Microsoft Reviewers: Open in CodeFlow

[codecov[bot]]

Codecov Report

Attention: 68 lines in your changes are missing coverage. Please review.

Comparison is base (2441a36) 73.16090% compared to head (1f6382e) 73.14391%.

Additional details and impacted files

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Flag	Coverage Δ
Debug	73.14391% <5.55556%> (-0.01699%)	:arrow_down:
integration	18.22953% <ø> (+0.00316%)	:arrow_up:
production	46.60777% <ø> (-0.02063%)	:arrow_down:
test	94.97593% <5.55556%> (-0.01852%)	:arrow_down:
unit	43.51462% <ø> (-0.04544%)	:arrow_down:

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[JeremyKuhne]

Sorry @weltkante - wrapped up in some other things. Hope to get a look in a few days.

[weltkante]

Sorry @weltkante - wrapped up in some other things. Hope to get a look in a few days.

No rush on this one, its not blocking anything, and in fact "just works" (once the remaining open points are decided), so its just about getting better coverage.

[weltkante]

Small update since the old code didn't build anymore inside VS after the recent .NET 9 preview was released, so I rebased onto the current main branch.

Seems the first draft wasn't working properly, VS was running x64 so the test was skipped and I mistakingly thought it worked, now it also works when running x86 tests and is actually executing the code.

While fixing this I noticed that the test project containing the AxHost tests is different from the test project containing the NativeTests.dll - so I tried adding a dependency to the CMake NativeTests but doesn't seem to work. If I copy the files (dll, tlb, manifest) manually it does work locally.

Maybe this particular AxHost test needs to move into the other project?

Anyways, no reason to priorize this, I just wanted to get it in working order before looking at the other ActiveX issues I have on my todo list ;-)