Minitest for Crystal

Unit tests and assertions for the Crystal programming language, using the fantastic minitest as reference.

Getting Started

Given that you'd like to test the following class:

class Meme
  def i_can_has_cheezburger?
    "OHAI!"
  end

  def will_it_blend?
    "YES!"
  end
end

Unit Tests

Define your tests as methods beginning with test_:

require "minitest/autorun"

class MemeTest < Minitest::Test
  def meme
    @meme ||= Meme.new
  end

  def test_that_kitty_can_eat
    assert_equal "OHAI!", meme.i_can_has_cheezburger?
  end

  def test_that_it_will_not_blend?
    refute_match /^no/i, meme.will_it_blend?
  end

  def test_that_will_be_skipped
    skip "test this later"
  end
end

Specs

Specs follow the same design rationale than the original Minitest: describe generates classes that inherit from Minitest::Spec, and it generates test methods.

require "minitest/autorun"

describe Meme do
  let(:meme) { Meme.new }

  describe "when asked about cheeseburgers" do
    it "must respond positively" do
      meme.i_can_has_cheezburger?.must_equal("OHAI!")
    end
  end

  describe "when asked about blending possibilities" do
    it "won't say no" do
      meme.will_it_blend?.wont_match(/^no/i)
    end
  end
end

You may use assertions in your specs (they'll work the same) or you may prefer the expect syntax:

expect(meme.i_can_haz_cheezeburger?).must_equal("OHAI!")
expect(meme.will_it_blend?).wont_match(/^no/i)

Run Tests

Eventually run the tests:

$ crystal test/meme_test.cr spec/meme_spec.cr -- --verbose

You may filter your tests using an exact test name, or a regexp:

$ crystal test/meme_test.cr -- -n test_that_kitty_can_eat
$ crystal test/meme_test.cr -- -n /will/

When using Minitest::Spec with assertions or the expect syntax, you can avoid to taint Object with all the #must_ and #wont_ expectations:

$ crystal -Dmt_no_expectations spec/meme_spec.cr

License

Distributed under the MIT License. Please see LICENSE for details.

Credits

• Julien Portalier @ysbaddaden for the Crystal implementation
• Ryan Davis @zenspider and seattle.rb for the original Ruby gem