diff-so-fancy/hacking-and-testing.md

Good-lookin' diffs with diff-highlight and more

### Hacking

```sh
# fork and clone the diff-so-fancy repo.
git clone https://github.com/so-fancy/diff-so-fancy/ && cd diff-so-fancy

# test a saved diff against your local version
cat test/fixtures/ls-function.diff | ./diff-so-fancy

# setup symlinks to use local copy
npm link
cd ~/projects/catfabulator && git diff
```

### Running tests

The tests use [bats-core](https://bats-core.readthedocs.io/en/latest/index.html), the Bash automated testing system.

```sh
# initalize the bats components
git submodule sync && git submodule update --init

# run the test suite once:
./test/bats/bin/bats test

# run it on every change with `entr`
brew install entr
find  ./* test/* test/fixtures/* -maxdepth 0 | entr ./test/bats/bin/bats test
```

When writing assertions, you'll likely want to compare to expected output. To grab that reliably, you can use something like `git --no-pager diff | ./diff-so-fancy > output.txt`