Exkorpion

An Elixir framework to do testing in a BDD way

Installation

Library is available in Hex, the package can be installed as:

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

```elixir
def deps do
  [{:exkorpion, "~> 0.0.3"}]
end
```

In case of you don't have a elixir environment ready to code, please have a look at the below links:

• Elixir installation
• Mix introduction
• Mix dependencies

Exkorpion goals

• It wraps ExUnit and enhances their features providing developers with a BDD syntax.

• It helps us to write tests wasy-to-read.

• It is completely compatible with ExUnit.

• It force us to structure our tests in steps (given-when-then)

• It is based on a functional syntax, organization our tests steps by anonymous functions.

• It is not coupled to any other framework.

Getting started

Exkorpion syntax

As was mentioned on the above Exkorpion is mainly oriented to a bdd syntax:

scenario: A scenario groups multiple cases that test a functionality works as expected. By using scenario we achieve the below:

• Better documentation for other developers.
• Test are better organized and structured
• Working under an agile methodology we can match scenarios to acceptance criteria

it: Exkorpion provide with a reserved word It to represent any of the cases inside a scenario.

    scenario "testing sum operation works as expected" do

       it "sum positive numbers works as expected" do

       end

       it "sum negative numbers and it should work as expected" do

       end

    end

with/given/when/then: These word are the ones that provide us with s BDD syntax. Actually even when we write some unit tests we should thinkg about them.

• Given: It defines the input data for performing the tests. (It's an optional step, it could be not neccessary sometimes)
• When: It performs the action to be tested.
• Then: It ensures the result in the preoviuos step are the expected.

  it "Ensures that get tracks service returns always 2 elements" do
    %{
      when: fn _ ->
        %{result: build_conn() |> get("/tracks", "v1") |> json_response |> Poison.decode! }
      end,  
      then: fn ctx ->
        assert 2 === length(ctx.result)
      end   
    }
  end

we could make us of with* step if we pretend to run the some tests for multiple input

  it "Ensures that add new track service works as expected" do
    %{
      with: fn ctx ->
          [
            %{new_track: %{"title" => "Runaway", "singer" => "John Bon Jovi"}},
            %{new_track: %{"title" => "Let her go", "singer" => "The passenger"}},
          ]
      end,
      given: &(%{new_track_json: &1.new_track |> Poison.encode!, previous_tracks: build_conn() |> get("/tracks", "v1") |> json_response |> Poison.decode! }),
      when: fn ctx ->
        %{result: build_conn() |> put_body_or_params(ctx.new_track) |> post("/tracks", "v1") |> json_response |> Poison.decode! }         

      end,  
        then: fn ctx ->
          assert length(ctx.previous_tracks)+1 === length(ctx.result)
          assert true === Enum.member?(ctx.result, ctx.new_track)
        end   
    }
  end

before_each: Before each will be inside of a scenario and provices with a reusable set of data for our tests.

  scenario "testing sum operation works as expected" do
  
    before_each do
      %{a: 10}
    end

    it "sum positive numbers works as expected" do
      %{
        given: &(%{a: &1.a, b: 3}),
        when: &(%{c: &1.a + &1.b}),
        then: fn ctx ->
          assert ctx.c === 13
        end
      }
    end

    it "sum negative numbers and it should work as expected" do
      %{
        given: &(%{a: &1.a, b: -2}),
        when: &(%{c: sum(&1.a ,&1.b)}),
        then: fn ctx ->
          assert ctx.c === 8
        end
      }
    end

  end

First steps

• Once we have added exkorpion dependency to our test we can run the below command. This will creae a scenario directory on our poejct with a file named scenario_helper.exs.

    mix exkorpion.init

• By default Exkorpion will search files ended by ".._scenario.exs" inside directory scenarios. This could be easyly customized (We explain in following articles.)

• We can write one or more scenarios per file

• To run the exkorpion scenarios we just need to run

    MIX_ENV=test mix exkorpion

• Exkorpion provides with a friendly resume about our tests execution.

Success execution

Something went wrong!

Samples

It's highly recommendable you to have a look at some samples already developed:

• Exkorpion project
• Maru training

Contributors

• Iván Corrales Solera : You could reach me by , email, twitter or Linkedin