Add Test Coverage to All Modules

[Miserlou]

It looks like all of the modules in this stack don't have code coverage. This makes it difficult as a user/new contributor to see how well tested these modules are, and it makes it more difficult for you as maintainers to see if incoming pull requests are appropriately testing all the code paths that they may be introducing.

I use the coverage and coveralls services on all of my projects and have found them quite useful. It seems that the istanbul library is kind of the go-to Node alternative here, but I think that anything would be better than nothing here.

That being said, I understand if you have your own objections (ex, well covered != well integrated) about this and I can close this.

Just a suggestion that would be appreciated!

[feross]

I don't see the value in code coverage tools. You can run them locally if you care, but they've never been helpful to me.

[Miserlou]

I think there is pretty great value:

• Easily see the general state of how healthy and tested a codebase is (for the parts I'm using, it's ~80% coverage, ~60% of paths, for the curious)
• Get an at-a-glance view of which features are tested and which aren't
• Track over-time if the reliability of the code is increasing or decreasing
• Maintainers can easily see if PRs introduce untested code
• Contributors can see which areas of the code need additional test coverage, which gives new contributors a starting point and existing contributors better ownership of their code.

I'm curious what other contributors think about this. Test coverage is a pretty standard part of modern FOSS tooling so I was surprised that this stack didn't use it, especially considering how many projects are starting to depend on it, my own included. ¯_(ツ)_/¯

[josephfrazier]

I think @Miserlou makes some good points. In any case, adding code coverage as part of CI doesn't seem like it would have any downsides (assuming a README badge and a PR comment/status don't count).

@Miserlou, maybe you could use your fork to show what this might look like? That way there would be something more concrete to discuss. For example, I did this on another project at nvbn/thefuck#566

P.S. It looks like istanbul is already used by zuul, so we might be able to have browser test coverage statistics as well!

[DiegoRBaquero]

I like the idea, it adds more information. I don't see how it could impact negatively in any way.

[feross]

I don't have any immediate plans to work on this issue, so I'm going to close it.

[lock]

This thread has been automatically locked because it has not had recent activity. To discuss futher, please open a new issue.