Run cleanup() when test runner supports teardown()

[screendriver]

What:

cleanup() now runs not only when afterEach() exists. It also runs when teardown() exists.

Why:

There are test runners that either don't have a afterEach() function or supports different UI's, like Mocha's TDD UI for example. It would be great if react-testing-library would also support teardown() for cleaning up things.

How:

I just added an additional check that checks and calls teardown() instead of beforeEach().

Checklist:

• Documentation added to the
  docs site
• Tests
• Typescript definitions updated
• Ready to be merged
  

The main problem that I have with this pull request is:

• linting fails because teardown is not defined. Is this somewhere deep in eslint-config-kentcdodds?
• I had problems to write a test for that because you are using Jest which does not have teardown()

[codesandbox-ci]

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Latest deployment of this branch, based on commit f461860:

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muddy-rgb-1h307	Configuration

[screendriver]

Now the tests fail because code coverage is below the threshold. Wich leads to my second point

• I had problems to write a test for that because you are using Jest which does not have teardown()

[eps1lon]

I think you can tell coverage to ignore certain branches. Something like instanbul ignore-if or so. Should be able to find this via google "jest coverage ignore".

[codecov]

Codecov Report

Merging #676 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #676   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines           99       100    +1     
  Branches        15        16    +1     
=========================================
+ Hits            99       100    +1     

Impacted Files	Coverage Δ
src/index.js	100.00% <100.00%> (ø)

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[screendriver]

@eps1lon I ignored the else block and the build is now green

[kentcdodds]

Awesome! Thank you!

I wonder whether we should consider this a breaking change 😬

[screendriver]

I wonder whether we should consider this a breaking change 😬

Good question. I guess not? I mean, nothing will break. It's "just" a new feature for (for example) Mocha users like me 🙃

[kentcdodds]

@all-contributors please add @screendriver for code

[allcontributors]

@kentcdodds

I've put up a pull request to add @screendriver! 🎉