fix(jest): pass findRelatedTests files as positional args

[just-jeb]

Problem

Fixes #2150

Root cause

Angular CLI passes comma-separated CLI values as a single string for array-type schema fields. So:

ng test --find-related-tests file1,file2

...arrives at OptionsConverter as options.findRelatedTests = 'file1,file2' (a string, not an array).

The existing string branch then emits:

--findRelatedTests=file1,file2

But Jest declares --findRelatedTests as a boolean yargs option. When yargs sees --findRelatedTests=file1,file2 for a boolean option, it coerces the value → false, and no positional file paths land in argv._. Result: Pattern: file1,file2 - 0 matches.

Why is this only surfacing now?

This was always broken — it just wasn't widely reported. The feature has been available since the original find-related-tests schema addition (2019), and the README even documents the comma-separated syntax as the correct way to pass multiple files. The bug affects anyone trying to use it.

Fix

Introduce POSITIONAL_ARRAY_OPTIONS — a set of option names that Jest treats as a boolean flag with file paths as trailing positional arguments (parsed via yargs _). For these options, the converter:

1. Splits the comma-separated string into individual paths
2. Emits the boolean flag once: --findRelatedTests
3. Appends the paths as positional args at the end of argv

Result for ng test --find-related-tests file1,file2:

--findRelatedTests file1 file2

Jest yargs parsing: findRelatedTests=true, _=['file1', 'file2'] ✅

Also handles array values (e.g. from angular.json) for the same options.

Tests

Added four unit tests to options-converter.spec.ts covering:

• Comma-separated string (the Angular CLI case)
• Single file path string
• Array value (from angular.json)
• Correct positioning of positional args after other flags