expect: Improve report when matcher fails, part 8

[pedrottimark]

Summary

For .toBeCloseTo matcher:

• Display matcher name in regular black instead of dim color
• Display expected and received difference to make criterion more transparent
• Repeat not following Expected: and Expected difference: labels
• Experiment to omit received value if it is equal to the not expected value (am happy if y’all can suggest as an alternative a concise explicit way to communicate that is reason why test fails)

For more information, see discussion with @jeysal in #7795

Residue for future pull requests:

1. In call to ensureNumbers helper function:

   • delete period in matcher name to display matcher name in regular black instead of dim color
   • provide options as argument to display promise and isNot

2. Decide whether .toBeCloseTo throws matcher error:

   • when expected or received is NaN
   • when precision argument is not integer number

Test plan

Updated 17 snapshot tests

See also pictures in following comments

[pedrottimark]

Review pictures as if they have updated default format for differences in following #7876 (comment)

16 example pictures baseline at left and improved at right

6 expected is finite number

4 expected is Infinity

3 expected is -Infinity

3 expected is NaN

JavaScript is consistent if confusing that NaN is not equal to NaN

[jeysal]

So much nicer 👌

Agreed that it would be great to have a message without duplicate values if expected and received are equal, but one that still shows clearly why the assertion failed. Can't spontaneously think of a good way to do it that would be consistent with the regular message format though :/

Also, unconditionally using scientific notation might not be a good idea:

I think the default of Number.toString() that only uses scientific notation if a string representation would otherwise be very long might suffice?

[pedrottimark]

Yes, simpler is much clearer to compare expected and received differences! What was I thinking?

Two updated improved examples are side by side:

[codecov-io]

Codecov Report

Merging #7876 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7876      +/-   ##
==========================================
+ Coverage   58.46%   58.52%   +0.05%     
==========================================
  Files         178      178              
  Lines        6638     6647       +9     
  Branches        6        5       -1     
==========================================
+ Hits         3881     3890       +9     
  Misses       2755     2755              
  Partials        2        2

Impacted Files	Coverage Δ
packages/expect/src/matchers.js	99.48% <100%> (+0.02%)	⬆️

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[SimenB]

this is awesome

[pedrottimark]

Almost a year later, we finally found a way to follow up on review #5512 (comment) by Michał:

I'd move precision below received

[SimenB]

I'm sure he's dancing with joy 💃

[thymikee]

🕺

[github-actions]

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