DescribeFunction

Inspired by a conversation on Twitter, DescribeFunction adds an additional layer of TDD to your Elixir application.

Usage

defmodule ExampleTest do
  use ExUnit.Case, asnyc: true

  import DescribeFunction

  describe_function &Example.hello_world/0 do
    test "hello_world functions as expected" do
      assert Example.hello_world() == "hello world"
    end
  end
end

Assuming your Example module implements hello_world/0, your test will pass or fail, based on its implementation. On the other hand, if Example.hello_world/0 is undefined, running your tests will raise

** (DescribeFunction.UndefinedFunctionError) function not defined: &Example.hello_world/0

The describe_function/2 macro validates that the function you are testing is defined. This will catch untested changes to your application's API at a high level in your test suite, resulting in a single, straightforward error, rather than many errors that might occur at a more removed level of your API.

Installation

If available in Hex, the package can be installed by adding describe_function to your list of dependencies in mix.exs:

def deps do
  [
    {:describe_function, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/describe_function.