stig

Simple test input generation.

What is it

Stig is a small library for property based testing in Ruby. It runs a test multiple times (100 by default) with randomly generated input. Stig is test framework agnostic, so can be used with any test framework.

Usage

An example using cutest. test and assert_raise come from cutest.

require "stig"

test "doesn't parse random input" do
  Stig.property(String) do |string|
    assert_raise { Library.parse(string) }
  end
end

Stig.property takes one or more generators and a predicate block. A generator is an object implementing #call or #random. A predicate block is a block that returns true for passed tests and false for failed test.

Note: In the above example String is used as generator. Stig doesn't monkey-patch any core classes.

Generators

Stig ships with a few built in generators, such as Date, Integer and String. They can be found under the Stig::Generators namespace. It's easy to write your own generators using Stig.generator and Stig.generator_for.

An example of creating a custom generator using Stig.generator.

Person = Struct.new(:name, :age)

person_generator = generator do
  Person.new Generators::String.random, Generators::Integer.random(99)
end

person_generator.call
# => #<struct Person name="M#uVfd7\tx\x1Eri]\x1F\x7F", age=95>

An example of creating a custom generator using Stig.generator_for.

Person = Struct.new(:name, :age) do
  def self.random
    new Generators::String.random, Generators::Integer.random(99)
  end
end

person_generator = generator_for(Person)

person_generator.call
# => #<struct Person name="-\x069|\x0F\x03Llq", age=6>

To configure the number of tests stig should run set the environment variable STIG_NUMBER_OF_RUNS to the desired number of test runs.

Installation

gem install stig

Stig requires Ruby 1.9.3 or higher.

License