# Writing the Bible

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* [Adding Code to the Bible.](#adding-code-to-the-bible)
* [Special meanings for code blocks.](#special-meanings-for-code-blocks)
* [Writing tests](#writing-tests)
* [Running tests](#running-tests)

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## Adding Code to the Bible.

- The code must use only `bash` built-ins.
    - A fallback to an external program is allowed if the code doesn't
      always work.
    - Example Fallback: `${HOSTNAME:-$(hostname)}`
- If possible, wrap the code in a function.
    - This allows tests to be written.
    - It also allows `shellcheck` to properly lint it.
    - An added bonus is showing a working use-case.
- Write some examples.
    - Show some input and the modified output.


## Special meanings for code blocks.

Use `sh` for functions that should be linted and unit tested.

    ```sh
    # Shellcheck will lint this and the test script will source this.
    func() {
        # Usage: func "arg"
        :
    }
    ```

Use `shell` for code that should be ignored.

    ```shell
    # Shorter file creation syntax.
    :>file
    ```

## Writing tests

The test file is viewable here: https://github.com/dylanaraps/pure-bash-bible/blob/master/test.sh

Example test:

```sh
test_upper() {
    result="$(upper "HeLlO")"
    assert_equals "$result" "HELLO"
}
```

Steps:

1. Write the test.
    - Naming is `test_func_name`
    - Store the function output in a variable (`$result` or `${result[@]}`).
    - Use `assert_equals` to test equality between the variable and the
      expected output.
2. The test script will automatically execute it. :+1:


## Running tests

Running `test.sh` also runs `shellcheck` on the code.

```sh
cd pure-bash-bible
./test.sh
```