Coverage - provide a way to exclude lines or branches from coverage

[keverw]

What is the problem this feature would solve?

Sometimes might be edge cases or rare that you might want to exclude or delegated to helper functions. For example I'm making a little CLI tool and made a very minimalist logger utility, process.exit I'd never actually call. So in my tests I just overwrote the .exit() method.

bun test v1.0.17 (5e60861c)

logger.test.ts:
✓ Logger should log an error in red [1.36ms]
✓ Logger should log info in white [0.07ms]
✓ Logger should log a warning in yellow [0.05ms]
✓ Logger should log success in green [0.05ms]
✓ Logger should log a note in blue [0.06ms]
✓ Logger should log correctly and handle exit [0.12ms]
-----------|---------|---------|-------------------
File       | % Funcs | % Lines | Uncovered Line #s
-----------|---------|---------|-------------------
All files  |   71.43 |   92.86 |
 index.ts  |   71.43 |   92.86 | 5
-----------|---------|---------|-------------------

What is the feature you are proposing to solve the problem?

A way to add a comment similar to Istanbul.

For example:

/ istanbul ignore if /: ignores the next if statement. / istanbul ignore else /: ignores the else portion of an if statement. / istanbul ignore next /: ignores the next thing in the source-code ( functions, if statements, classes, you name it). So for example it can ignore the entire tree possibly. / istanbul ignore file /: ignores an entire source-file (this should be placed at the top of the file). / istanbul ignore else|if /: Ignores a “else if” - but it has to be at the top of the tree:

What alternatives have you considered?

Not really any ideas, my plan is to just keep working on my project and if there's a better way to do this, it'd be great otherwise something I can live with.

[elringus]

This is actually an essential feature for a production-ready test/coverage system, and one of the blockers (others being https://github.com/oven-sh/bun/issues/4015, https://github.com/oven-sh/bun/issues/7100) stopping me from switching to bun test.

Other popular test frameworks have this from v1, eg in vitest: https://vitest.dev/guide/coverage.html#ignoring-code (similar works in jest).

Hopefully this could be added to the roadmap. @Electroid

[jtenner]

I just hit this problem too. For now, I have to reduce test coverage size, because what I'm testing dynamically creates modules using a BunPlugin.

It would be nice to be able to skip an entire module.

[roninjin10]

I'm migrating https://github.com/evmts/tevm-monorepo to vitest in future because of this issue

[Jarred-Sumner]

we can add a way to do this, particularly if the first implementation is just the next line

[MKRhere]

@Jarred-Sumner That won't do, I can't do an ignore for each line in a const enum that's bringing down coverage...

I would prefer to have something like /* coverage ignore start */ and /* coverage ignore end */.