Review test coverage and performance of generated code

[mrlacey]

• Check coverage of tests against generated apps
• ~Tidy up magic strings used throughout test code~ done as part of #3799
• Add better handling for different functionality available for different languages/frameworks (some pages are currently not tested to avoid this)
• Look to optimize test performance
• Look at the possibility of improving logging information for debugging test failures
• Look at combining tests to reduce overall execution time. (Acknowledging that test should only test one thing but the potential for performance gains makes this worth exploring)
• add UI tests for WPF apps

Follow on from #3722 X-Ref #3723 #3758

[mrlacey]

Suggest deferring this until after MVVMBasic and CaliburnMicro templates are removed as there will be a lot of opportunities for refactoring of existing UWP templates and how templates are tested at that time.

[mrlacey]

removing assignment as this is not expected to happen until removal of CM, MB, & ML templates

[mikebattista]

@mrlacey is there any work remaining here given the latest roadmap and test refactoring in place?

[mrlacey]

@mrlacey is there any work remaining here given the latest roadmap and test refactoring in place?

Can we leave this open:

• We still don't have any coverage information (& I expect it's low)
• There are lots of opportunities to further improve the structure of the testing code. (It's been through a "make it work" phase" but not yet a "make it better" one).