test: improve dns lookup coverage

[KeeReal]

Adding tests covering promises-related code paths.

missing coverage

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[Trott]

@nodejs/dns @nodejs/testing

[Trott]

@KeeReal Welcome and thanks for the pull request. Are you able to point to the lines of code that are currently uncovered that this will cover? Or at least what file those lines of code would be in?

[KeeReal]

Hi @Trott.
Sure, here you go - https://coverage.nodejs.org/coverage-cc3f2b386c6ee34f/lib/internal/dns/promises.js.html#L34
These two functions onlookup and onlookupall were not covered and this change covers all code paths within them

[Trott]

@joyeecheung (just in case you want to test on any particularly restrictive networks--I tested with the network disconnected entirely and the test worked fine, which I suppose is a good indication that the monkey-patching has the intended effect, but just in case....)

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/27415/

[bcoe]

@KeeReal were you able to run coverage locally to make sure that you hit the target lines:

NODE_V8_COVERAGE=./cov ./node test/parallel/test-dns-lookup-promises.js
./node_modules/.bin/c8 report --reporter=html \
	--temp-directory=./cov --omit-relative=false \
	--resolve=./lib --exclude="benchmark/" --exclude="deps/" --exclude="test/" --exclude="tools/" \
	--wrapper-length=0
open coverage/index.html

[bcoe]

this looks good to me, conditional on confirming that this test exercises the expected code.

[KeeReal]

Thx, @bcoe
I double checked this and noticed that I missed one thing - when a family option is explicitly passed to getaddrinfo.
Added another case to cover this

[BridgeAR]

RSLGTM

Mocking is definitely not ideal but this part can probably not be tested properly otherwise.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/27587/ ✅ (yellow build with two typical Windows flakes)

[BridgeAR]

Landed in 2d13896 🎉