Windows mocha test times out from time to time

[cristianoc]

Locally on m1 Mac js_array_test needs 9 ms:

/node_modules/.bin/mocha -t 9 jscomp/test/js_array_test.js

while on Windows CI it often times out at 2000ms: https://github.com/rescript-lang/rescript-compiler/runs/7064506583?check_suite_focus=true

[cristianoc]

Unclear whether a bigger timeout is the solution, as the difference is too big.

[jchavarri]

Mocha tests are running with "global" stdio, maybe that's the reason?

https://github.com/rescript-lang/rescript-compiler/blob/d3f0840ce31f406a3ecd6d98c81d26042573647e/scripts/ciTest.js#L110-L112

[cristianoc]

Mocha tests are running with "global" stdio, maybe that's the reason?

https://github.com/rescript-lang/rescript-compiler/blob/d3f0840ce31f406a3ecd6d98c81d26042573647e/scripts/ciTest.js#L110-L112

Could be. Know how to avoid that?

[jchavarri]

Removing line 112 😄

[cristianoc]

Removing line 112 😄

Then how do we know why a test failed?

[cristianoc]

Error: Command failed: npx mocha -t 100 jscomp/test/**/*test.js
    at checkExecSyncError (node:child_process:817:11)
    at Object.execSync (node:child_process:888:15)
    at runTests (/Users/cristianocalcagno/GitHub/rescript-compiler/scripts/ciTest.js:110:8)
    at main (/Users/cristianocalcagno/GitHub/rescript-compiler/scripts/ciTest.js:165:5)
    at Object.<anonymous> (/Users/cristianocalcagno/GitHub/rescript-compiler/scripts/ciTest.js:171:1)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Module._load (node:internal/modules/cjs/loader:827:12) {
  status: 1,
  signal: null,
  output: [
    null,
    <Buffer 38 0a 62 73 5f 68 61 73 68 74 62 6c 5f 73 74 72 69 6e 67 5f 74 65 73 74 2e 6d 6c 20 32 30 33 3a 20 31 31 31 2e 34 32 37 6d 73 0a 35 0a 78 79 0a 35 0a ... 157016 more bytes>,
    <Buffer >
  ],
  pid: 7825,
  stdout: <Buffer 38 0a 62 73 5f 68 61 73 68 74 62 6c 5f 73 74 72 69 6e 67 5f 74 65 73 74 2e 6d 6c 20 32 30 33 3a 20 31 31 31 2e 34 32 37 6d 73 0a 35 0a 78 79 0a 35 0a ... 157016 more bytes>,
  stderr: <Buffer >
}

[cristianoc]

Not the most informative failure.

[jchavarri]

hm you're right 🤔

[jchavarri]

actually what I suggested does not make sense because the issue with hanging was happening on async functions, but in this case execSync is used.

[cristianoc]

Looks like it's just Windows being slow.
Increased the timeout to 5000ms here, and run a zillion times.
They all worked fine.

https://github.com/rescript-lang/rescript-compiler/runs/7067958053?check_suite_focus=true