mocha --watch doesn't work with v6.0.0

[fcruzel]

Prerequisites

• Checked that your issue hasn't already been filed by cross-referencing issues with the faq label
• Checked next-gen ES issues and syntax problems by using the same environment and/or transpiler configuration without Mocha to ensure it isn't just a feature that actually isn't supported in the environment in question or a bug in your code.
• 'Smoke tested' the code to be tested by running it outside the real test suite to get a better sense of whether the problem is in the code under test, your usage of Mocha, or Mocha itself (only tested in my machine, in the same project).
• Ensured that there is no discrepancy between the locally and globally installed versions of Mocha. You can find them with: node node_modules/.bin/mocha --version(Local) and mocha --version(Global). We recommend avoiding the use of globally installed Mocha. (N/A - no global version installed)

Description

mocha --watch doesn't detect the tests. Output: 0 passing (10 ms). It did in the 5.2.0 version.

Steps to Reproduce

Update to 6.0.0, write a test or use the ones you already have and try to execute the watcher. mocha will work, mocha --watch wont.

Expected behavior: [What you expect to happen]

• mocha --watch detect the tests,
• and executes every time a test or a src file change.

Actual behavior: [What actually happens]

• mocha --watch doesn't detect any test.

Reproduces how often: [What percentage of the time does it reproduce?]

100%

Versions

• The output of mocha --version and node node_modules/.bin/mocha --version: 6.0.0
• The output of node --version: 11.9.0
• The version and architecture of your operating system: Ubuntu 18.04.1 LTS, 4.15.0-45-generic x86_64
• Your shell (bash, zsh, PowerShell, cmd, etc.): bash
• Your browser and version (if running browser tests): N/A
• Any other third party Mocha related modules (with versions): chai@4.2.0
• The code transpiler being used:

Additional Information

[ghinks]

I can confirm that I am seeing similar issues. I just tried version 6 and the --watch is not working as it was in 5. I am working on a mac book pro. I pushed branch up to show the issue.

npm run test:watch-mocha

if you downgrade to mocha 5, watch will start working.

This is a typescript based project of my own but simpler pure JS projects have the same issue. I have updated the readme on this branch with instructions. I'm sure you may not need additional examples but here you are anyway.

[plroebuck]

Using Glen's repo, migrated all test related code into "test" directory.

$ DEBUG=mocha:watch mocha --require 'test/register.js' --watch 'src/**/*.ts' 'test/**/*.spec.ts' --extensions 'ts,js'

  0 passing (1ms)

  mocha:watch file /tmp/sample-node-typescript-module/src/foo.js +0ms
  mocha:watch file /tmp/sample-node-typescript-module/test/cmd/index.spec.js +2ms
  mocha:watch file /tmp/sample-node-typescript-module/test/register.js +0ms

Running this, I don't see any TypeScript files getting picked up (as though --watch-extensions was just ".js"). Adding JS files would increase output watched files.

Does it work for anyone on a vanilla JS project (i.e., no transpiling)?

[ghinks]

many thanks @plroebuck I created a plain vanilla repo with the same result. My sincere thanks to the mocha team. I know how hard it is to push out code 🥇

[fcruzel]

It doesn't work in my vanilla JS project neither, that's where I originally got the bug

[boneskull]

@plroebuck only --watch-extensions and --extension are currently valid (not --extensions)

[boneskull]

I'm having trouble reproducing any problems with @ghinks's repo. (thanks for the repo)

[boneskull]

(the typescript repo, anyway)

[boneskull]

OK, I can confirm a problem with the vanilla one

[boneskull]

OK, I think I have a fix. unfortunately the watch stuff is tough to test.

[boneskull]

see #3755