test: log errors in test-fs-readfile-tostring-fail

[richardlau]

The test writes out a large file via fs.createWriteStream() but was
not listening for the error event, which the fs docs describe as the
reliable way to detect write errors.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[nodejs-github-bot]

Lite-CI: https://ci.nodejs.org/job/node-test-pull-request-lite-pipeline/3145

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/22122/

[refack]

https://ci.nodejs.org/job/node-test-commit-linux/nodes=ubuntu1804-64/26640/
https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/5894/ ✔️ (had 1.2GB free)
https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/5896/ (staring with 580MB free) ✔️
https://ci.nodejs.org/job/node-test-commit-linux/nodes=ubuntu1804-64/26644 (moved back to sequential)

[richardlau]

For context: #16601 (comment)

The test is failing on that host because it has less than 1Gb of free disk space, so the file gets truncated and the error does not occur when the file is read. I think moving to pummel is the right answer after all.

I'd expect the test to detect that -- Is it ignoring errors when writing the file out?

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/22127/

[refack]

We're getting the same thing:

11:48:25 not ok 7 pummel/test-fs-readfile-tostring-fail
11:48:25   ---
11:48:25   duration_ms: 24.415
11:48:25   severity: fail
11:48:25   exitcode: 7
11:48:25   stack: |-
11:48:25     /mnt/iojs/node-test-commit-custom-suites-freestyle/test/pummel/test-fs-readfile-tostring-fail.js:69
11:48:25       throw err;
11:48:25       ^
11:48:25     
11:48:25     AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
11:48:25     
11:48:25       assert.ok(err instanceof Error)
11:48:25     
11:48:25         at /mnt/iojs/node-test-commit-custom-suites-freestyle/test/pummel/test-fs-readfile-tostring-fail.js:36:12
11:48:25         at /mnt/iojs/node-test-commit-custom-suites-freestyle/test/common/index.js:369:15
11:48:25         at FSReqCallback.readFileAfterClose [as oncomplete] (internal/fs/read_file_context.js:54:3)
11:48:25   ...

https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/5902/console

[refack]

Added 33947f7 to try to see other errors
https://ci.nodejs.org/job/node-test-commit-custom-suites-freestyle/5905/

Got 🍩 :

12:34:42 not ok 7 pummel/test-fs-readfile-tostring-fail
12:34:42   ---
12:34:42   duration_ms: 23.579
12:34:42   severity: fail
12:34:42   exitcode: 1
12:34:43   stack: |-
12:34:43   ...

[BridgeAR]

What's the status here?

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/22456/

[richardlau]

What's the status here?

Rebased and pushed out 33947f7 which broke the linter. Even if this doesn't reveal the original error that is causing the tests to flake on the CI it is no worse and is the correct way to detect write errors according to our documentation so I think we should land this.

[BridgeAR]

Still LGTM

[richardlau]

Landed in f85ef97.