test_test.rb

require 'abstract_unit'
require 'active_support/test_case'

class AssertDifferenceTest < Test::Unit::TestCase
  def setup
    @object = Class.new do
      attr_accessor :num 
      def increment
        self.num += 1
      end

      def decrement
        self.num -= 1
      end
    end.new    
    @object.num = 0
  end

  if lambda { }.respond_to?(:binding)
    def test_assert_no_difference
      assert_no_difference '@object.num' do
        # ...
      end
    end

    def test_assert_difference
      assert_difference '@object.num', +1 do
        @object.increment
      end
    end

    def test_assert_difference_with_implicit_difference
      assert_difference '@object.num' do
        @object.increment
      end
    end

    def test_arbitrary_expression
      assert_difference '@object.num + 1', +2 do
        @object.increment
        @object.increment
      end
    end

    def test_negative_differences
      assert_difference '@object.num', -1 do
        @object.decrement
      end
    end

    def test_expression_is_evaluated_in_the_appropriate_scope
      local_scope = 'foo'
      silence_warnings do
        assert_difference('local_scope; @object.num') { @object.increment }
      end
    end

    def test_array_of_expressions
      assert_difference [ '@object.num', '@object.num + 1' ], +1 do
        @object.increment
      end
    end

    def test_array_of_expressions_identify_failure
      assert_difference ['@object.num', '1 + 1'] do
        @object.increment
      end
      fail 'should not get to here'
    rescue Test::Unit::AssertionFailedError => e
      assert_equal "<1 + 1> was the expression that failed.\n<3> expected but was\n<2>.", e.message
    end

    def test_array_of_expressions_identify_failure_when_message_provided
      assert_difference ['@object.num', '1 + 1'], 1, 'something went wrong' do
        @object.increment
      end
      fail 'should not get to here'
    rescue Test::Unit::AssertionFailedError => e
      assert_equal "something went wrong.\n<1 + 1> was the expression that failed.\n<3> expected but was\n<2>.", e.message
    end
  else
    def default_test; end
  end
end

# These should always pass
class NotTestingThingsTest < Test::Unit::TestCase
  include ActiveSupport::Testing::Default
end

class AlsoDoingNothingTest < ActiveSupport::TestCase
end

# Setup and teardown callbacks.
class SetupAndTeardownTest < Test::Unit::TestCase
  setup :reset_callback_record, :foo
  teardown :foo, :sentinel, :foo

  def test_inherited_setup_callbacks
    assert_equal [:reset_callback_record, :foo], self.class.setup_callback_chain.map(&:method)
    assert_equal [:foo], @called_back
    assert_equal [:foo, :sentinel, :foo], self.class.teardown_callback_chain.map(&:method)
  end

  def setup
  end

  def teardown
  end

  protected
    def reset_callback_record
      @called_back = []
    end

    def foo
      @called_back << :foo
    end

    def sentinel
      assert_equal [:foo, :foo], @called_back
    end
end


class SubclassSetupAndTeardownTest < SetupAndTeardownTest
  setup :bar
  teardown :bar

  def test_inherited_setup_callbacks
    assert_equal [:reset_callback_record, :foo, :bar], self.class.setup_callback_chain.map(&:method)
    assert_equal [:foo, :bar], @called_back
    assert_equal [:foo, :sentinel, :foo, :bar], self.class.teardown_callback_chain.map(&:method)
  end

  protected
    def bar
      @called_back << :bar
    end

    def sentinel
      assert_equal [:foo, :bar, :bar, :foo], @called_back
    end
end