feat: adds utility launch for debugging a single test file

[mschnee]

Partially implements: #4300
See: #4406

This has been split from #4406 as a more manageable, smaller PR.

This update adds a developer convenience Launch task to allow debugging a single unit test file in Visual Studio Code.

Adds

• bin/mocha-current-file.js - this is a utility script that attempts to determine the dist output of the given test file, and passes it off to mocha in-process.
• VSCode: Debug Current Test File launch configuration. This launch configuration allows you to debug the current unit test file currently focused. It uses the above helper to determine the correct name and path of the compiled JavaScript file to run.

Modifies

• The launch for "Run Mocha Tests" so that it also runs on Windows.

Checklist

• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

[mschnee]

There are a couple of instances (e.g. debugging packages/metadata/src/__tests__/decorator-factory.unit.ts) where breakpoints don't get picked up as expected. This could be the "autoAttachChildProcesses": true, in the launch configuration.

[mschnee]

NOTE: I have rebased from upstream and squashed all commits, which should address the travis commitlint and doc errors.

[bajtos]

Nice! The changes look reasonably, I have two small comments to address.

[mschnee]

Sorry for the delay in getting back to this PR! I had a brief vacation. Will update and address things :)

[mschnee]

With approvals from @raymondfeng and @bajtos I'd be happy to merge this in :)

[bajtos]

Welcome back, @mschnee. I am looking forward to see this improvement landed 🤸‍♂️

I am afraid I found few details that I am not very happy with, can you please fix them? See my comments below and also Raymond's comment about wrong copyright year(s) in the license header.

Thank you!

[mschnee]

Addressing the commitlint changes :)

[derdeka]

👏 Thanks, works well for me with Windows 10.

feat(build): adds launch for debugging a single test file

nitpick: Please change the commit message, as it does not effekt the build package anymore.

[mschnee]

@derdeka What's the correct scope? core?

[bajtos]

What's the correct scope? core?

core is for changing affecting @loopback/core package.

In this case, I think it's best to leave the scope out. Also please note that we are using imperative form ("add something"), not present tense ("adds something"). See subject in our Commit Message Guidelines and also A Note About Git Commit Messages.

I am proposing the following commit message:

feat: add a launch task for debugging a single test file

(Personally, I would choose chore instead of feat because this change is not visible to LoopBack users, but that does not really matter.)

[bajtos]

LGTM 👏

Please update the commit message per my comment above before landing.

[raymondfeng]

Nitpick: the current code has a theoretical possibility of infinite loop as it does not test the root of a file system. A more robust implementation can be:

let pkgFile = path.resolve(filename, '../package.json');

// Find root directory of the file system
const root = path.parse(pkgFile).root;

while (!fs.existsSync(pkgFile)) {
  if (path.dirname(pkgFile) === root) {
    // We reach the root of file system
    pkgFile = undefined;
    break;
  }
  // Try the parent directory level package.json
  pkgFile = path.resolve(pkgFile, '../../package.json');
}

if (!pkgFile) return filename; // Or throw an error
const projectRoot = path.dirname(pkgFile);
const relative = path.relative(projectRoot, path.resolve(filename));
const jsFilePath = relative.replace(/^src/, 'dist').replace(/\.ts$/, '.js');
return path.resolve(projectRoot, jsFilePath);

[mschnee]

I made a small change to the current function, and tested it by invoking this cli against both a test file inside of the loopback-next workspace, and also a fake.test.js file that has no package.json file in it's filesystem heirarchy