Fix #3292: Add check for test files presence for prod files

[Sparsh1212]

Explanation

Fixes #3292: Add check for test files presence for prod files

The script traverses different layers of the codebase to check for the presence of test files for prod files.

Note: It works on the logic of searching Filename+'Test'.kt in the codebase, to ensure the test file presence.
The files listed in the test_file_exemptions.textproto will be skipped for this check, and currently, all the prod files which were failing this check, have been added to this list so that the workflow doesn't fail.
We can remove any file from the exemption list, where we think that we can't go without a test file for that prod file, or if a test file is now added for that particular file.

To run the script, use:

bazel run //scripts:test_file_check -- $(pwd)

For testing the script, automated tests have been added.
To execute the tests, use:

bazel test //scripts/src/javatests/org/oppia/android/scripts/testfile:TestFileCheckTest

Note: We are generating the test assets dynamically at the time of executing them. The test assets are automatically deleted, when the test finishes.

Blocked on: #3341 #3340

Screenshot of all new added tests passing successfully on local:

Checklist

• The PR title starts with "Fix #bugnum: ", followed by a short, clear summary of the changes. (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• The PR explanation includes the words "Fixes #bugnum: ..." (or "Fixes part of #bugnum" if the PR only partially fixes an issue).
• The PR follows the style guide.
• The PR does not contain any unnecessary auto-generated code from Android Studio.
• The PR is made from a branch that's not called "develop".
• The PR is made from a branch that is up-to-date with "develop".
• The PR's branch is based on "develop" and not on any other branch.
• The PR is assigned to an appropriate reviewer in both the Assignees and the Reviewers sections.

[anandwana001]

Thanks, @Sparsh1212

The same comment applies here from your previous PR regarding the script .kt file and its test file.

[BenHenning]

Thanks @Sparsh1212. Generally LGTM, but two questions:

1. Can you please bring this branch up-to-date with develop now that Fix #3291: Add check for XML syntax validation #3341 is merged & update the title to no longer indicate it's blocked
2. Can you clear the textproto file & show what the CI failure looks like for an empty exemption list? I'm interested in verifying the failure cases in a real CI scenario
3. After (2), please restore the textproto file so that CI is green (the result should be 1 commit with the specific failures requested from (2) and the latest commit passing)

[Sparsh1212]

@BenHenning
The test commit added!
Also, note that one test will fail, because we have also removed the exempted file which is needed by the exempted file test. So, its a expected behaviour.

[BenHenning]

Thanks @Sparsh1212. LGTM! Just waiting for green CI to merge.

[oppiabot]

Unassigning @BenHenning since they have already approved the PR.

[oppiabot]

Assigning @seanlip for code owner reviews. Thanks!

[BenHenning]

@Sparsh1212 looks like the new check is failing in CI--please fix.

[seanlip]

I'm a bit confused ... why is Oppiabot assigning me to this PR? I don't code-own any files in it.

[BenHenning]

@seanlip looks like a potential bug. You were auto-added as a reviewer because a base PR changed the codeowners file. I guess Oppiabot assumes that reviewers always get auto-assigned even if they aren't a codeowner or at-mentioned?

[BenHenning]

Thanks @Sparsh1212. Everything is looking good. Enabling auto-merge.

[seanlip]

Oh, weird. Hm, I'm not too bothered about it, but if it recurs it might be worth fixing on Oppiabot's end. /cc @jameesjohn for info.

[jameesjohn]

@seanlip looks like a potential bug. You were auto-added as a reviewer because a base PR changed the codeowners file. I guess Oppiabot assumes that reviewers always get auto-assigned even if they aren't a codeowner or at-mentioned?

Yes. oppiabot assumes that reviewers who are yet to review a PR are to be assigned.