assert: show diff when doing partial comparisons with a custom message

[puskin94]

following the same reasoning as this PR:

right now the method assert.partialDeepStrictEqual does not show the diff when the assertion fails.
With this PR we go from this:

const assert = require('assert');

assert.partialDeepStrictEqual([1, 2, 3, 5], [4, 5]);

to this

with a custom error message:

Relevant changes:

1. enabled the diff when assert.partialDeepStrictEqual fails
2. enabled the diff when assert.partialDeepStrictEqual fails with a custom error message
3. added different diff style in case assert.partialDeepStrictEqual fails:

• properties available in actual are gray
• properties in expected but not in actual are prefixed with the classic red -
• properties present in both actual and expected are white

[BridgeAR]

How to show the diff for the partial implementation has been one of my main concerns for a while and my current idea is to grey out or hide all lines that are not in the expected object. That way it would be more straight forward for the user.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.55%. Comparing base (3851edf) to head (9f449e9).
Report is 93 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #56211      +/-   ##
==========================================
+ Coverage   88.49%   88.55%   +0.05%     
==========================================
  Files         656      657       +1     
  Lines      189261   190405    +1144     
  Branches    36348    36561     +213     
==========================================
+ Hits       167493   168609    +1116     
- Misses      14977    14990      +13     
- Partials     6791     6806      +15     

Files with missing lines	Coverage Δ
lib/assert.js	99.37% <100.00%> (+0.27%)	⬆️
lib/internal/assert/assertion_error.js	95.44% <100.00%> (+0.07%)	⬆️
lib/internal/assert/myers_diff.js	90.05% <100.00%> (+0.23%)	⬆️

... and 70 files with indirect coverage changes

[puskin94]

Is there anything left to be done here?

[BridgeAR]

LGTM!

Let's see how people react to the greyed out part to gather feedback while it's experimental. I feel it is nicer than the green plus.

[BridgeAR]

Suggested change

	// TODO(puskin94): remove the emitWarning override once the partialDeepStrictEqual method is not experimental anymore
	// Suppress warnings, necessary otherwise the tools/pseudo-tty.py runner will fail
	const originalEmitWarning = process.emitWarning;
	process.emitWarning = () => {};
	// Suppress warnings, necessary otherwise the tools/pseudo-tty.py runner will fail
	const originalEmitWarning = process.emitWarning;
	process.emitWarning = common.mustCall(() => {});

That way the test would fail when it is not called anymore when removing the warning.

The same in the other files.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/64146/