Update build-and-test to prevent merging fdescribe and fit

[Nateowami]

It's very easy to accidentally include fdescribe and fit when opening a PR. This has happened multiple times, most recently in #2373 (which actually has an approved review, and I was about to merge).

This PR updates the build workflow to grep for fdescribe( and fit( across all .spec.ts files, and fails the build if they are present.

It's also possible to accidentally include xdescribe and xit, but sometimes those will be intentional, and generally it's only a few tests that would be skipped over.

This PR changes a describe to fdescribe to demonstrate that the change works. Therefore, it deliberately fails the build. After being reviewed, I will revert that one change so it can be merged.

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This change is 

[pmachapman]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @Nateowami)

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.github/workflows/build-and-test.yml line 87 at r1 (raw file):

        # grep returns code 123 when no matches are found. The operator ! negates the exit code.
        run: |
          ! git ls-files | grep "\\.spec\\.ts" | xargs grep -P "(fdescribe|fit)\("

This regex might be a bit too broad - it will pick up fdescribe/fit in comments, or method names like unfit().

Should we limit it to fdescribe/fit preceded by whitespace, from the start of the line?

git ls-files | grep "\\.spec\\.ts" | xargs grep -P "^\s*(fdescribe|fit)\("

Code quote:

git ls-files | grep "\\.spec\\.ts" | xargs grep -P "(fdescribe|fit)\("

[Nateowami]

Reviewable status: 1 of 2 files reviewed, 1 unresolved discussion (waiting on @pmachapman)

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.github/workflows/build-and-test.yml line 87 at r1 (raw file):

Previously, pmachapman (Peter Chapman) wrote…

This regex might be a bit too broad - it will pick up fdescribe/fit in comments, or method names like unfit().

Should we limit it to fdescribe/fit preceded by whitespace, from the start of the line?

git ls-files | grep "\\.spec\\.ts" | xargs grep -P "^\s*(fdescribe|fit)\("

Good improvement. Done.

[pmachapman]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @Nateowami)