ExUnitFixtures

A library for defining modular dependencies (fixtures) for ExUnit tests.

What are Fixtures?

Fixtures in ExUnitFixtures are just functions that are run before a test.

They can be used to setup the tests environment somehow, or provide the test with some data that it requires. Similar in purpose to setup & setup_all but more powerful:

• Tests explicitly list what fixtures they require, ensuring that no un-neccesary setup work is done.
• Fixtures may be shared across many tests in a project.
• Fixtures may depend on or override other fixtures, allowing core fixtures to be used & customised as each subsystem or test module requires.

Installation

1. Add ex_unit_fixtures to your list of dependencies in mix.exs:

def deps do
  [{:ex_unit_fixtures, "~> 0.3.1", only: [:test]}]
end

Documentation

The documentation can be found on hexdocs.pm: http://hexdocs.pm/ex_unit_fixtures/ExUnitFixtures.html

Example

Say some of your tests required a model named my_model. You should define a fixture fixture using deffixture, then tag your test to say it requires this fixture:

defmodule MyTests do
  use ExUnitFixtures
  use ExUnit.Case

  deffixture my_model do
    # Create a model somehow...
    %{test: 1}
  end

  @tag fixtures: [:my_model]
  test "that we have some fixtures", context do
    assert context.my_model.test == 1
  end
end

More details can be found in the documentation.

Examples in the wild.

• Vassal makes use of ExUnitFixtures in it’s integration tests.
• I have played around with converting the tests for Sqlitex to use ExUnitFixtures. (This hasn’t been PRd, it’s just another example).