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[![codecov](https://codecov.io/gh/AtakamaLLC/cover-diff/branch/master/graph/badge.svg)](https://codecov.io/gh/AtakamaLLC/cover-diff)

# cover-diff

Report & enforce diff coverage on diffs only.

### Install:

```
npm install @atakama/cover-diff
```

### Use:

Pipe in diffs, get an lcov file out.

```bash
git diff origin/master | cover-diff > diff-cover.lcov
genhtml diff-cover.lcov -o diff-cover
```

Note:

If you don't have genhtml, do this:

```
curl -O https://raw.githubusercontent.com/linux-test-project/lcov/master/bin/genhtml
chmod +x genhtml
./genhtml diff-cover.lcov -o diff-cover
```

That works in most bashifed environments (including Windows under git bash).

### Options:

Options are located in the `package.json` for your project.  The default lcov path is the same as the istanbul default output path.

```bash
"@atakama/cover-diff" : {
    "lines" : 80,
    "branches" : 70,
    "functions" : 100,
    "lcovFile" : "coverage/lcov.info",
    "diffFile" : \<stdin\>,
    "stripRoot" : [<project-home-dir>],
}
```


### Notes:

- Empty or invali diff : exit with an error, no stdout.
- Valid diff, but no lines in the diff match: no error exit, no stdout

### [Changelog](./CHANGELOG.md)