Fix unit tests to ensure that test registrations happen before tests.

[nsthorat]

Previously the test registries would happen as a function of imports. This doesn't ensure that unconstrained tests run after tests get registered.

This PR creates a setup_test.ts file like we do in WebGPU which imports the registries and then parses the karma flags. This ensures the expected order.

This PR also adds --testEnv as a command line flag instead of --backend.

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This change is 

[tafsiri]

Overall looks good, but i think there are some opportunities to make things clearer/more explicit.

Also update https://github.com/tensorflow/tfjs-core/blob/master/DEVELOPMENT.md

Reviewed 6 of 6 files at r1.
Reviewable status: complete! 1 of 1 approvals obtained (waiting on @annxingyuan, @nsthorat, and @tafsiri)

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karma.conf.js, line 64 at r1 (raw file):

  const args = [];
  if (config.testEnv) {
    args.push('--testEnv', config.testEnv);

What happens if no --testEnv is passed? (document that here?)

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scripts/enumerate-tests.js, line 44 at r1 (raw file):

const path = require('path');
const argv = require('yargs').argv;

Optional: Add some docs to describe the purpose of this file.

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src/jasmine_util.ts, line 64 at r1 (raw file):

}

export function parseKarmaFlags(

this should be renamed to indicate that is is specifically trying to parse TestEnv related info from flags.

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src/setup_test.ts, line 32 at r1 (raw file):

  const testEnv = parseKarmaFlags(__karma__.config.args, TEST_ENVS);
  if (testEnv != null) {
    setTestEnvs([testEnv]);

Not related to this line, but can we add a beforeAll check to the test runner infra to confirm that an environment has been set has been set before any test runs? (to guard against the files entry in config being modified.

[nsthorat]

Reviewable status: complete! 1 of 1 approvals obtained (waiting on @annxingyuan and @tafsiri)

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karma.conf.js, line 64 at r1 (raw file):

Previously, tafsiri (Yannick Assogba) wrote…

What happens if no --testEnv is passed? (document that here?)

Done.

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scripts/enumerate-tests.js, line 44 at r1 (raw file):

Previously, tafsiri (Yannick Assogba) wrote…

Optional: Add some docs to describe the purpose of this file.

Done.

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src/jasmine_util.ts, line 64 at r1 (raw file):

Previously, tafsiri (Yannick Assogba) wrote…

this should be renamed to indicate that is is specifically trying to parse TestEnv related info from flags.

Done.

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src/setup_test.ts, line 32 at r1 (raw file):

Previously, tafsiri (Yannick Assogba) wrote…

Not related to this line, but can we add a beforeAll check to the test runner infra to confirm that an environment has been set has been set before any test runs? (to guard against the files entry in config being modified.

Done. I did this at the beginning of describeWithFlags before we iterate through the test envs.