Add common test for getting all types in each runtime library implementation assembly

[elinor-fung]

Some libraries don't have tests using every type (for example, internal types only used in hard to automate scenarios). It may be valuable to have a test that just loads all types in runtime libraries.

See:
#68240 (comment)
#68274 (comment)

cc @danmoseley

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

Tagging subscribers to this area: @dotnet/area-infrastructure-libraries
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Issue Details

---

Some libraries don't have tests using every type (for example, internal types only used in hard to automate scenarios). It may be valuable to have a test that just loads all types in runtime libraries.

See:
#68240 (comment)
#68274 (comment)

cc @danmoseley

Author:	elinor-fung
Assignees:	-
Labels:	area-Infrastructure-libraries, test-enhancement, untriaged
Milestone:	-

[ViktorHofer]

@elinor-fung As this is a test coverage problem I'm removing the infrastructure label and changing it to Meta.

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

Issue Details

---

Some libraries don't have tests using every type (for example, internal types only used in hard to automate scenarios). It may be valuable to have a test that just loads all types in runtime libraries.

See:
#68240 (comment)
#68274 (comment)

cc @danmoseley

Author:	elinor-fung
Assignees:	-
Labels:	area-Meta, test-enhancement, untriaged
Milestone:	-

[danmoseley]

as mentioned in the original comment -- do folks think this trick would work, so we only write a single test: we put it in a common file that was included in all test assemblies, with a single test that enumerates all loaded assemblies and does GetTypes on each.
potential issues

• does it matter that the same fully qualified test name is in multiple assemblies
• how do we make this test run late (last?) so to ensure any relevant product assembly is already loaded

[elinor-fung]

enumerates all loaded assemblies and does GetTypes on each

It'd be nice if we could narrow it down more, since I think there would be a lot of duplication in what is being tested. Do libraries tests assemblies have any tracking / way of determining what the product assembly under test is? If the test 'knows' what the target product assembly is, it could explicitly load and get all types.