Added a should_fail macro to help test failure scenarios in the cor…

…e shoulda tests

test/fail_macros.rb

@@ -0,0 +1,34 @@
+module Thoughtbot
+  module Shoulda
+    class << self
+      attr_accessor :expected_exceptions
+    end
+
+    # Enables the core shoulda test suite to test for failure scenarios.  For
+    # example, to ensure that a set of test macros should fail, do this:
+    #
+    #   should_fail do
+    #     should_require_attributes :comments
+    #     should_protect_attributes :name
+    #   end
+    def should_fail(&block)
+      context "should fail when trying to run:" do
+        Shoulda.expected_exceptions = [Test::Unit::AssertionFailedError]
+        yield block
+        Shoulda.expected_exceptions = nil
+      end
+    end
+
+    class Context
+      # alias_method_chain hack to allow the should_fail macro to work
+      def should_with_failure_scenario(name, options = {}, &block)
+        if Shoulda.expected_exceptions
+          expected_exceptions = Shoulda.expected_exceptions
+          failure_block = lambda { assert_raise(*expected_exceptions, &block.bind(self)) }
+        end
+        should_without_failure_scenario(name, options, &(failure_block || block))
+      end
+      alias_method_chain :should, :failure_scenario
+    end
+  end
+end

test/test_helper.rb

@@ -5,15 +5,15 @@
 rails_root = File.dirname(__FILE__) + '/rails_root'
 
 require "#{rails_root}/config/environment.rb"
- 
+
 # Load the testing framework
 require 'test_help'
 silence_warnings { RAILS_ENV = ENV['RAILS_ENV'] }
- 
+
 # Run the migrations
 ActiveRecord::Migration.verbose = false
 ActiveRecord::Migrator.migrate("#{RAILS_ROOT}/db/migrate")
- 
+
 # Setup the fixtures path
 Test::Unit::TestCase.fixture_path = File.join(File.dirname(__FILE__), "fixtures")
 
@@ -25,7 +25,9 @@ def create_fixtures(*table_names)
       Fixtures.create_fixtures(Test::Unit::TestCase.fixture_path, table_names)
     end
   end
- 
+
   self.use_transactional_fixtures = false
   self.use_instantiated_fixtures  = false
 end
+
+require 'test/fail_macros'

test/unit/user_test.rb

@@ -44,4 +44,8 @@ class UserTest < Test::Unit::TestCase
   should_only_allow_numeric_values_for :ssn
 
   should_have_readonly_attributes :name
+
+  should_fail do
+    should_protect_attributes :name, :age
+  end
 end