Add custom reporter to reduce the test output

[willdurand]

Fix mozilla/addons#10682
⚠️ depends on #5871

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That works on my machine™️ Maybe we should test this reporter, but I don't really know how. I guess we'll notice when things will break :D

[codecov-io]

Codecov Report

Merging #5872 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    mozilla/addons-frontend#5872      +/-   ##
==========================================
+ Coverage   97.72%   97.72%   +<.01%     
==========================================
  Files         228      228              
  Lines        5763     5764       +1     
  Branches     1105     1105              
==========================================
+ Hits         5632     5633       +1     
  Misses        116      116              
  Partials       15       15

Impacted Files	Coverage Δ
src/amo/sagas/collections.js	100% <0%> (ø)	⬆️

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[willdurand]

rebased.

[kumar303]

I say this is ready to ship once it has a name.

This is pretty good! Some notes:

• I wanted it to only show the output for a failing test but it shows the output for the whole suite. This is better than before but less than ideal.
• When I run a single test (in watch mode I type t and then filter by test spec), it doesn't show any output at all. This is what was mentioned in jestjs/jest#6441 . I chased this down a bit until I finally realized that without your custom reporter, it still doesn't even show output. So, yeah, it's a bummer but this means at least your reporter isn't making things worse.
• The buffering code in Jest is really complicated so I don't know if we'll ever get grouped output as requested in jestjs/jest#2080 .

[kumar303]

I think it's ready for a proper name! I'd suggest putting it in a directory called tests/jest-reporters/

[willdurand]

Isn't it already a proper name? We hope we won't need to output console logs, that's the idea behind this name :) It is borrowed from https://github.com/Seldaek/monolog/blob/master/src/Monolog/Handler/FingersCrossedHandler.php#L19

[willdurand]

I wanted it to only show the output for a failing test but it shows the output for the whole suite. This is better than before but less than ideal.

Yep I saw that too, but it is better than absolutely all logs. We don't have too many test cases per test suite. It is a baby step toward a better developer experience.

[kumar303]

I thought the name was just a placeholder while you got it working but I get it now. The comment above the reporter explains what it does so 🤷‍♀️

[Scimonster]

Maybe consider spinning this off into its own module so other people can easily take advantage of it?

[willdurand]

Maybe consider spinning this off into its own module so other people can easily take advantage of it?

Not sure, it works well for us in this project but I am not sure it is generic enough to be reused elsewhere.