Improve code coverage for System.ComponentModel.TypeConverter (56%)

[chlowell]

The code coverage report shows us at 47% for the next version of the package (currently in dev/typedescriptor). Improving this will mostly require work around TypeDescriptor. The largest gaps in its coverage are in private code requiring more elaborate scenarios to reach than what we have in unit tests.

[hughbe]

I might be misunderstanding something here: I ran the coverage report for System.ComponentModel.TypeConverter and got 88% line and 83% branch coverage

Report Summary

[Clockwork-Muse]

...given that there are platform-specific tests and behaviors (in general, I don't know about this specific case), perhaps it should be stated up front if the given library does any of that, or what the platform was. Oh, and if OuterLoop was used, since that may also have an effect.

[chlowell]

Sorry, I should have been more clear: we're at 47% coverage for the next version of the package, which currently lives in dev/typedescriptor.

[danmoseley]

The coverage is only 24%

https://ci.dot.net/job/dotnet_corefx/job/master/job/code_coverage_windows/Code_Coverage_Report/

[WinCPP]

I have not yet tried test enhancements for code coverage. Given that background, I would like to try writing a few for this issue. May I?

Per the link that @danmosemsft shared above, current coverage is 36.4% (Line) and 27.4% (Branch) for TypeDescriptor. @chlowell mentiones about 47% in dev/typedescriptor, but in next version of the package (not sure if I understand that clearly). Am I on the verge of duplicating the efforts if I don't refer to next version coverage...? Thanks!

[danmoseley]

@WinCPP you're welcome. I would say some code coverage exercises are probably higher importance than ComponentModel though. Places where coverage is even lower, or type usage is higher.

For example XML is huge, heavily used and not got great coverage in some places:
https://github.com/dotnet/corefx/issues/16650
https://github.com/dotnet/corefx/issues/16649
https://github.com/dotnet/corefx/issues/16646

and others
https://github.com/dotnet/corefx/labels/increase-code-coverage

Up you you -- all is welcome.

As you may know here's the all up report
https://ci.dot.net/job/dotnet_corefx/job/master/job/code_coverage_windows/Code_Coverage_Report/
Big caveat- doesn't show coverage of any types whose implementation is in corelib (eg STring, etc). If you want to look at that for now you must gather manually using instructions below.

Docs on code coverage work are here
https://github.com/dotnet/corefx/blob/master/Documentation/building/code-coverage.md
and some in
https://github.com/dotnet/corefx/blob/master/Documentation/project-docs/developer-guide.md

Let us know if you want an assignment!

[WinCPP]

@danmosemsft Thanks for the reply. I think I will take a stab at dotnet/corefx#16646. Will continue more on that thread... Thanks!

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