Fix #1887: Thoroughly test FractionInputHasNumeratorEqualToRuleClassifierProvider

[TheRealJessicaLi]

@BenHenning PTAL

Explanation

Fixes #1887 by adding unit tests for FractionInputHasNumeratorEqualToRuleClassifierProvider.

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).
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• 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".
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[BenHenning]

Thanks @TheRealJessicaLi! Apologies for the delayed review. This looks good--just left a couple of comments including some ideas for additional tests.

[rt4914]

@TheRealJessicaLi Please do not do any force push. (cc @BenHenning )

[BenHenning]

Thanks @TheRealJessicaLi. PR LGTM!

Couple things:

1. When resolving a comment thread, please 'resolve' it by leaving a comment (not by clicking the 'resolve' button). Authors will resolve the thread after verifying it's resolved. This helps us keep better track of comments since longer PRs have dozens of them across multiple review passes.

2. As @rt4914 mentioned, please never force submit. There are rare occasions where it's necessary, and if you hit such a case please follow up with us first. Force submission breaks history (per its nature), which leads to losing comments & conversation threads. In this case, I needed to re-review the whole PR rather than just your latest changes.