test: add unexpected disconnect guards to more client test files

[samayer12]

This relates to...

Relates to #251 and #4833.

Rationale

Adds a guardDisconnect() helper to unit tests that previously used the more verbose pattern seen in #4833. This PR also adds the guard function to additional tests that do not already adopt the pattern. Docs are also updated for future test authors.

I think that 8e69a9f also resolves a test cleanup issue in CI with node 20 tests on macos-latest, seen here.

Note that c8 fails coverage in CI and is related to bcoe/c8#581 and bcoe/c8#582.

Changes

This PR recommended structuring tests along these lines:

test('example with disconnect guard', async (t) => {
  t = tspl(t, { plan: 1 })

  const client = new Client('http://localhost:3000')
  after(() => client.close())

  guardDisconnect(client, t)

  // ... test logic ...
})

Following feedback, we prefer to make the function utility explicit and just provide a set of assertions calculated. Therefore, we'll stick with:

  client.on('disconnect', () => {
    if (!client.closed && !client.destroyed) {
      t.fail('unexpected disconnect')
    }
  })

Here are the benchmark results from a local run:

[bench:run] ┌─────────┬───────────────────────┬─────────┬────────────────────┬────────────┬─────────────────────────┐
[bench:run] │ (index) │ Tests                 │ Samples │ Result             │ Tolerance  │ Difference with slowest │
[bench:run] ├─────────┼───────────────────────┼─────────┼────────────────────┼────────────┼─────────────────────────┤
[bench:run] │ 0       │ 'http - no keepalive' │ 50      │ '5752.85 req/sec'  │ '± 2.82 %' │ '-'                     │
[bench:run] │ 1       │ 'got'                 │ 70      │ '11935.17 req/sec' │ '± 2.93 %' │ '+ 107.47 %'            │
[bench:run] │ 2       │ 'node-fetch'          │ 30      │ '11967.99 req/sec' │ '± 2.80 %' │ '+ 108.04 %'            │
[bench:run] │ 3       │ 'undici - fetch'      │ 35      │ '14422.02 req/sec' │ '± 2.91 %' │ '+ 150.69 %'            │
[bench:run] │ 4       │ 'axios'               │ 15      │ '14573.42 req/sec' │ '± 2.56 %' │ '+ 153.33 %'            │
[bench:run] │ 5       │ 'request'             │ 25      │ '15760.95 req/sec' │ '± 2.87 %' │ '+ 173.97 %'            │
[bench:run] │ 6       │ 'http - keepalive'    │ 20      │ '17944.82 req/sec' │ '± 2.91 %' │ '+ 211.93 %'            │
[bench:run] │ 7       │ 'superagent'          │ 20      │ '18427.55 req/sec' │ '± 2.58 %' │ '+ 220.32 %'            │
[bench:run] │ 8       │ 'undici - pipeline'   │ 30      │ '22861.79 req/sec' │ '± 2.98 %' │ '+ 297.40 %'            │
[bench:run] │ 9       │ 'undici - request'    │ 20      │ '26651.34 req/sec' │ '± 2.94 %' │ '+ 363.27 %'            │
[bench:run] │ 10      │ 'undici - dispatch'   │ 25      │ '27216.23 req/sec' │ '± 2.64 %' │ '+ 373.09 %'            │
[bench:run] │ 11      │ 'undici - stream'     │ 15      │ '27222.67 req/sec' │ '± 2.74 %' │ '+ 373.20 %'            │
[bench:run] └─────────┴───────────────────────┴─────────┴────────────────────┴────────────┴─────────────────────────┘

Features

N/A

Bug Fixes

N/A

Breaking Changes and Deprecations

None

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• Benchmarked (optional)
• Documented
• Review ready
• In review
• Merge ready

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.14%. Comparing base (85cde5d) to head (2737414).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4844   +/-   ##
=======================================
  Coverage   93.14%   93.14%           
=======================================
  Files         109      109           
  Lines       34239    34239           
=======================================
  Hits        31891    31891           
  Misses       2348     2348           

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