@@ -15,6 +15,33 @@ module ThoughtBot # :nodoc: end fixtures *all_fixtures end + + # Macro that creates a test asserting the numeric difference between the + # return value of an expression that is run before and after the current + # setup block is run. This is similar to Active Support's + # <tt>assert_difference</tt> assertion. + # + # Example: + # + # context "Creating a post" + # setup do + # Post.create + # end + # + # should_differ "Post.count", :by => 1 + # end + # + # While not shown in this example, the <tt>:by</tt> option is optional + # and defaults to <tt>1</tt>. + def should_differ(expression, options = {}) + difference = options[:by] || 1 + expression_evaluation = lambda { eval(expression) } + before = lambda { @_should_differ_value = expression_evaluation.bind(self).call } + should "differ '#{expression}' by #{difference}", :before => before do + assert_equal @_should_differ_value + difference, expression_evaluation.bind(self).call + end + end + end # Prints a message to stdout, tagged with the name of the calling method. lib/shoulda/general.rb @@ -76,5 +76,22 @@ class HelpersTest < Test::Unit::TestCase # :nodoc: assert_same_elements([@a, "abc"].flatten, [3, 3, "def", "abc"]) end end + + context "after adding another value" do + setup do + @a.push("another") + end + + # testing the default :by option of 1 + should_differ "@a.length" + end + + context "after adding 3 more values" do + setup do + @a.push(1, 2, 3) + end + + should_differ "@a.length", :by => 3 + end end end test/other/helpers_test.rb e6e2f6b906edc4ecd6d7f8a77046216e308d1cf0 Ryan McGeary ryanongit@mcgeary.org http://github.com/rmm5t/shoulda/commit/9294040046ea64d6c93a92fe3c01f453f3d8450a 9294040046ea64d6c93a92fe3c01f453f3d8450a 2008-07-08T19:05:46-07:00 2008-07-08T19:05:46-07:00 Added new should_differ macro; akin to Active Support's assert_difference. 36e8211eb8ae7ee1ef0b7e0bc8cffeb519779257 Ryan McGeary ryanongit@mcgeary.org