require File.dirname(__FILE__) + '/abstract_unit' 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 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' assert_difference 'local_scope; @object.num' do @object.increment end end end