A mix task to execute eunit tests.

* Works in umbrella projects.
* Tests can be in the module or in the test directory.
* Allows the user to provide a list of patterns for tests to run.

mix eunit # run all the tests
mix eunit --verbose "foo*" "*_test" # verbose run foo*.erl and *_test.erl


Add to your `mix.exs` deps:

def deps
  [#... existing deps,
   {:mix_eunit, "~> 0.2"}]


mix deps.get
mix deps.compile
mix eunit

To make the `eunit` task run in the `:test` environment, add the following
to the `project` section of you mix file:

def project
  [#... existing project settings,
   preferred_cli_env: [eunit: :test]

Command line options:

A list of patterns to match for test files can be supplied:

mix eunit foo* bar*

The runner automatically adds ".erl" to the patterns.

The following command line switch is also available:

* `--verbose/-v` - Run eunit with the `:verbose` option.
* `--cover/-c` - Run cover during the tests. See below.

Project Settings:

The following `mix.exs` project settings affect the behavior of `mix eunit`.

def project
    # existing project settings
    # run the `eunit` task in the `:test` environment
    preferred_cli_env: [eunit: :test],
    # set the output directory for `mix eunit --cover` reports
    #   the default is `./cover` (same as `mix test --cover`)
    test_coverage: [output: "_build/#{Mix.env}/cover"]


Note that `mix eunit --cover` and `mix test --cover` will not in
general cover the same source code with tests and therefore will
typically generate two independent coverage reports.  There may be
some overlap if your eunit and ExUnit tests cover some of the same

By default, `mix eunit --cover` produces coverage reports in HTML
format in the same `cover` directory that `mix test --cover` does.
The filenames are slightly different - `mix test --cover` produces files with
names like `my_source_file.html` whereas `mix eunit --cover` produces
files with names like `my_source_file.COVER.html`.  Therefore, the two
tasks do not overwrite one another's output.

You can override the `mix eunit --cover` output directory in your
`mix.exs` file as described above.

Test search path:

All ".erl" files in the src and test directories are considered.