# Criterion
A library to write ExUnit tests BDD style
## Installation
The package can be installed
by adding `criterion` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:criterion, "~> 0.1.0", only: [:test, :dev]}
]
end
```
## Usage
### Feature file
`test/features/Math.feature`
```feature
Feature: Math
Scenario: Square
Given a number greater than 1
When the number is multiplied by it self
Then the result is greater than the number
And pi is a constant
```
### Shared steps
`test/support/shared_steps.ex`
```elixir
defmodule Criterion.SharedSteps do
import Criterion
defstep "Given a number", _context, args do
min = args[:min] || 0
%{number: min Enum.random(0..100)}
end
end
```
### Test
`test/criterion_test.exs`
```elixir
defmodule CriterionTest do
use ExUnit.Case
import Criterion
alias Criterion.SharedSteps
feature "Math" do
setup do
{:ok, pi: 3.14}
end
scenario "Square" do
step("Given a number greater than 1",
from: SharedSteps, # use only if the reusable step is in another module
via: "Given a number" # use only if the reusable step has a different step name,
where: [min: 2] # use only when you want to pass arguments to the reusable step,
)
step "When the number is multiplied by it self", %{number: number} do
result = number * number
%{result: result} # will be merged to the test context
end
step "Then the result is greater than the number", %{result: result, number: number} do
assert result > number
end
# you can access data from the initial context of the test
step "And pi is a constant", %{pi: pi} do
assert pi == 3.14
end
end
end
end
```
### Generating feature files
```
mix criterion.gen.features
```
#### Options
- `--dir` - specify the directory to read test files from. default is `test`
- `--file` - to generate feature files for a list of test files
- `--output` - specify the directory to generate feature files in. default is `test/features`
### Generating test files
```
mix criterion.gen.tests
```
#### Options
- `--dir` - specify the directory to read feature files from. default is `test/features`
- `--file` - to generate test for a list of files
- `--output` - specify the directory to generate the test files in. default is `test/features`