Firestore: equality_matcher.ts: fix missing custom assertion failure message in deep equals

[dconeybe]

This PR fixes a bug in Firestore's unit/integration testing framework where a "deep equals" assertion check would omit the custom failure message, when it should have included the custom failure message.

For example, consider the following "expect" checks:

expect({foo: 42}, 'custom message').to.deep.equal({bar: 42});
expect({foo: 42}).to.deep.equal({bar: 42}, 'custom message');

Both of these checks will unconditionally fail because {foo: 42} does not "deep equal" {bar: 42}. Also, both the checks specify a custom failure message to be incorporated into the failure message, albeit in different ways.

The problem is that the custom message is not included in the ultimate failure message:

AssertionError: expected { foo: 42 } to roughly deeply equal { bar: 42 }

With the fix in this PR, the custom message is included in the failure message:

AssertionError: custom message: expected { foo: 42 } to roughly deeply equal { bar: 42 }

The root cause of the bug was the misconception that custom message would be specified as an argument to the function. The function signature was actually incorrectly typed as (r: unknown, l: unknown) => boolean, suggesting that it was supposed to compare r and l for equality. This coincidentally just happened to work because r was treated as the "expected" and the l argument was simply ignored, which worked because it was always undefined anyways. The type was fixed to (expected: unknown) => void.

The custom function also did not need to call utils.flag(this, 'message', msg) because the chai testing framework already makes this call, and when the custom function made the call it just clobbered the previously-set custom message with undefined.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 659343e

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (e037eee) and merge commit (cc68bbf).

Test Logs

• Base (e037eee): https://github.com/firebase/firebase-js-sdk/actions/runs/5729295511
• Merge (cc68bbf): https://github.com/firebase/firebase-js-sdk/actions/runs/5743241038

1. https://storage.googleapis.com/firebase-sdk-metric-reports/zYTlWq1zoX.html

[google-oss-bot]

Size Analysis Report ¹

Affected Products

No changes between base commit (e037eee) and merge commit (cc68bbf).

Test Logs

• Base (e037eee): https://github.com/firebase/firebase-js-sdk/actions/runs/5729295511
• Merge (cc68bbf): https://github.com/firebase/firebase-js-sdk/actions/runs/5743241038

1. https://storage.googleapis.com/firebase-sdk-metric-reports/H8jL4F4qVm.html