define_matcher.feature

Feature: define matcher

In order to express my domain clearly in my code examples
As an RSpec user
I want a shortcut to define custom matchers

Scenario: define a matcher with default messages
  Given a file named "matcher_with_default_message_spec.rb" with:
    """
    Spec::Matchers.define :be_a_multiple_of do |expected|
      match do |actual|
        actual % expected == 0
      end
    end

    describe 9 do
      it {should be_a_multiple_of(3)}
    end

    describe 9 do
      it {should_not be_a_multiple_of(4)}
    end

    # fail intentionally to generate expected output
    describe 9 do
      it {should be_a_multiple_of(4)}
    end

    # fail intentionally to generate expected output
    describe 9 do
      it {should_not be_a_multiple_of(3)}
    end

    """
  When I run "spec matcher_with_default_message_spec.rb --format specdoc"
  Then the exit code should be 256

  And the stdout should match "should be a multiple of 3"
  And the stdout should match "should not be a multiple of 4"
  And the stdout should match "should be a multiple of 4 (FAILED - 1)"
  And the stdout should match "should not be a multiple of 3 (FAILED - 2)"

  And the stdout should match "4 examples, 2 failures"
  And the stdout should match "expected 9 to be a multiple of 4"
  And the stdout should match "expected 9 not to be a multiple of 3"

Scenario: overriding the failure_message_for_should
  Given a file named "matcher_with_failure_message_spec.rb" with:
    """
    Spec::Matchers.define :be_a_multiple_of do |expected|
      match do |actual|
        actual % expected == 0
      end
      failure_message_for_should do |actual|
        "expected that #{actual} would be a multiple of #{expected}"
      end
    end

    # fail intentionally to generate expected output
    describe 9 do
      it {should be_a_multiple_of(4)}
    end
    """
  When I run "spec matcher_with_failure_message_spec.rb"
  Then the exit code should be 256
  And the stdout should match "1 example, 1 failure"
  And the stdout should match "expected that 9 would be a multiple of 4"

Scenario: overriding the failure_message_for_should_not
  Given a file named "matcher_with_failure_for_message_spec.rb" with:
    """
    Spec::Matchers.define :be_a_multiple_of do |expected|
      match do |actual|
        actual % expected == 0
      end
      failure_message_for_should_not do |actual|
        "expected that #{actual} would not be a multiple of #{expected}"
      end
    end

    # fail intentionally to generate expected output
    describe 9 do
      it {should_not be_a_multiple_of(3)}
    end
    """
  When I run "spec matcher_with_failure_for_message_spec.rb"
  Then the exit code should be 256
  And the stdout should match "1 example, 1 failure"
  And the stdout should match "expected that 9 would not be a multiple of 3"

Scenario: overriding the description
  Given a file named "matcher_overriding_description_spec.rb" with:
    """
    Spec::Matchers.define :be_a_multiple_of do |expected|
      match do |actual|
        actual % expected == 0
      end
      description do
        "be multiple of #{expected}"
      end
    end

    describe 9 do
      it {should be_a_multiple_of(3)}
    end

    describe 9 do
      it {should_not be_a_multiple_of(4)}
    end
    """
  When I run "spec matcher_overriding_description_spec.rb --format specdoc"
  Then the exit code should be 0
  And the stdout should match "2 examples, 0 failures"
  And the stdout should match "should be multiple of 3"
  And the stdout should match "should not be multiple of 4"

Scenario: with no args
  Given a file named "matcher_with_no_args_spec.rb" with:
    """
    Spec::Matchers.define :have_7_fingers do
      match do |thing|
        thing.fingers.length == 7
      end
    end

    class Thing
      def fingers; (1..7).collect {"finger"}; end
    end

    describe Thing do
      it {should have_7_fingers}
    end
    """
  When I run "spec matcher_with_no_args_spec.rb --format specdoc"
  Then the exit code should be 0
  And the stdout should match "1 example, 0 failures"
  And the stdout should match "should have 7 fingers"

Scenario: with multiple args
  Given a file named "matcher_with_multiple_args_spec.rb" with:
    """
    Spec::Matchers.define :be_the_sum_of do |a,b,c,d|
      match do |sum|
        a + b + c + d == sum
      end
    end

    describe 10 do
      it {should be_the_sum_of(1,2,3,4)}
    end
    """
  When I run "spec matcher_with_multiple_args_spec.rb --format specdoc"
  Then the exit code should be 0
  And the stdout should match "1 example, 0 failures"
  And the stdout should match "should be the sum of 1, 2, 3, and 4"

Scenario: with helper methods
  Given a file named "matcher_with_internal_helper_spec.rb" with:
    """
    Spec::Matchers.define :have_same_elements_as do |sample|
      match do |actual|
        similar?(sample, actual)
      end

      def similar?(a, b)
        a.sort == b.sort
      end
    end

    describe "these two arrays" do
      specify "should be similar" do
        [1,2,3].should have_same_elements_as([2,3,1])
      end
    end
    """
  When I run "spec matcher_with_internal_helper_spec.rb"
  Then the exit code should be 0
  And the stdout should match "1 example, 0 failures"