docs: Add example of generating tests with a HOF

[maxwellgerber]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions.

Description of the Change

Quick docs update showing a workaround with some common issues run into w/data-driven tests.

Namely, it's very hard to run a single testcase from an IDE because tests inside a .forEach callback aren't detected, Compare

with

Alternate Designs

N/A (docs update)

Why should this be in core?

N/A (docs update)

Benefits

This approach has been useful for me & my team - hope it can be useful for someone else too

Possible Drawbacks

Slightly more verbose than pure data-driven approach.

Applicable issues

[jsf-clabot]

All committers have signed the CLA.

[coveralls]

Coverage remained the same at 94.129% when pulling a5cccfe on maxwellgerber:patch-1 into 9122909 on mochajs:master.

[boneskull]

Thanks! Good addition. I have a couple suggestions--happy to discuss.

[boneskull]

yeah that coveralls failure doesn't make sense. we've had this problem before. unclear to me if the culprit is coveralls or nyc...

[boneskull]

thanks for the updates. I have some more suggestions

[boneskull]

Test failure looks like timing-related flake; unrelated

[boneskull]

missed one

[juergba]

@maxwellgerber thank you
The cancelled browser test is off-topic.