feat: support for transforming runner

[Mark1626]

Summary

Allow jest-runner to be transformable.

Part of #8810

Test plan

Have added test case for the change

[Mark1626]

@SimenB e2e for pnp seems to fail, can you explain how it works, I don't have much context on it

[Mark1626]

After much tedious debugging the culprit seems to be pirates, it seems to mutate Module._extensions

[Object: null prototype] {
      '.js': [Function],
      '.json': [Function],
      '.node': [Function],
      '': [Function] } // <- This is added

pnp is trying to module.load on node_modules/istanbul-reports/lib/json the mutation caused in Module._extensions is making it load the directory instead of the index.js.

I'll try to dig into pirates and see if it's expected or an issue

[Mark1626]

Line that's the problem

https://github.com/facebook/jest/blob/95688ac9c81c19ca1bbda3aaad2a278c2a60461f/packages/jest-transform/src/ScriptTransformer.ts#L478

[codecov-io]

Codecov Report

Merging #8854 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #8854      +/-   ##
==========================================
+ Coverage   64.73%   64.73%   +<.01%     
==========================================
  Files         277      277              
  Lines       11707    11708       +1     
  Branches     2874     2875       +1     
==========================================
+ Hits         7578     7579       +1     
  Misses       3512     3512              
  Partials      617      617

Impacted Files	Coverage Δ
packages/jest-core/src/TestScheduler.ts	65.67% <100%> (+0.25%)	⬆️

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[Mark1626]

Rebased it against the current master

Not sure what's the problem with CI, it's only failing for macOS, and surprisingly enough I ran it against master in my local and I got the same.

  System:
    OS: macOS 10.15.5
    CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
  Binaries:
    Node: 12.19.0
    Yarn: 2.3.3-git.20201112.db30c005
    npm: 6.14.8
  npmPackages:
    jest: workspace:* => 26.6.3

[SimenB]

@Mark1626 I've opened up #10828 to track the CI failure

[SimenB]

Also, could you rebase (or just merge in master) again? Conflicts with #8751

[Mark1626]

I'll rebase it

[SimenB]

Suggested change

	"jest-environment-node": "^26.6.2"
	"jest-environment-node": "file:../../../packages/jest-environment-node"

does that work? to avoid hard-coding a version

---

do we even need these dependencies? I don't see yarn being run in here

[Mark1626]

I'll check, the changes were made before yarn berry came in, with the file: protocol I'll see if it works

[Mark1626]

It works with the file: protocol in my local, updating in both here and the jest-env PR

[github-actions]

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