Simple approach to run just the tests you need when building for the CLI

[sebastienlevert]

Hello team!

I was wondering what was you approach to run just the tests you needs when you are building for the CLI. Not that it's "super" long to build than to run the entire test suite, but just to find your command, look at how it goes... It can sometimes overwhelming and I wanted to find a better option. Let me know if you see any other brilliant option!

I tried to look at the mocha extensions for vscode and none of them really worked for what I was looking for without adding dependencies to the project and I did not want to do that. So I decided to go the more "custom" way.

So I did the following :

• npm install -g npx to allow me to execute npm run commands
• npm run watch to run the project in watch mode
• npx mocha "dist/**/app-user-list.spec.js" --watch to run the mocha tests in watch mode. You could use whatever glob you want to look for.

It's now giving me this, and I'm pretty happy with it! I can continuously validate my tests while I add capabilities to the commands I'm working on.

Do you see any drawbacks? With this, I'm not able to run the code coverage as it only runs it on the command you are watching, meaning that all the references are only partially covered in your command. Or is there a way better approach (maybe even already in the CLI) I was not able to find?

Thoughts? What is YOUR go-to for this kind of productive debugging?

[waldekmastykarz]

I'm going about it in two ways:

1. In package.json, I'm adding a new script that matches only the specific test file, eg. "test:dev": "c8 mocha \"dist/**/Utils.spec.js\"". That way I can have mocha run just these tests, which is pretty fast. One thing you need to keep in mind is that you should remember to remove this script before committing your changes
2. You can add .only either to the whole suite (describe statement) or a single test (it), eg. describe.only(..... That way mocha will run only this one suite/test. You can add .only to one or multiple tests/suites. One drawback is, that without modifying the test script, mocha will still parse all matching files, but will just run tests flagged with .only

Like you noticed, neither approach is useful for the coverage but helpful when building tests.

[sebastienlevert]

What about we add this test:dev to the list of available npm scripts? We could even use npm parameters to execute it, similar to the following :

"scripts": {
  "test:dev": "c8 mocha"
}

And then calling it using :

npm run test:dev -- "dist/**/user-app-list.spec.js"

I think this would be a nice developer experience and would actually help creating better tests, in the end!

[waldekmastykarz]

Given how much you'd need to type yourself (the file path glob) is there really an added value to have c8 mocha in package.json? 😉

[waldekmastykarz]

On a related note, I've been thinking about including VSCode config for debugging. Thinking about improving dev experience, I think that would be helpful. I just didn't get to it. Is this perhaps something you'd look into (or maybe you already have 😉)?

[sebastienlevert]

For the c8 mocha in package json, it's just that if it's there, I don't have to remember to remove it when I'm done ;) I did have a look at the debugging config and really came up with anything brilliant, but if you want I could dive a bit deeper! Maybe this would actually fix the issue and offer a better devx!