0
@@ -182,9 +182,20 @@ module ThoughtBot # :nodoc:
0
       # <tt>value</tt> by making sure the <tt>error_message_to_avoid</tt> is not
0
       # contained within the list of errors for that attribute.
0
       #
0
-      #   assert_good_value(User.new, :email, "user@example.com") #=> passes
0
-      #   assert_good_value(User.new, :ssn, "123456789", /length/) #=> passes
0
-      def assert_good_value(object, attribute, value, error_message_to_avoid = //)
0
+      #   assert_good_value(User.new, :email, "user@example.com")
0
+      #   assert_good_value(User.new, :ssn, "123456789", /length/)
0
+      #
0
+      # If a class is passed as the first argument, a new object will be
0
+      # instantiated before the assertion.  If an instance variable exists with
0
+      # the same name as the class (underscored), that object will be used
0
+      # instead.
0
+      #
0
+      #   assert_good_value(User, :email, "user@example.com")
0
+      #
0
+      #   @product = Product.new(:tangible => false)
0
+      #   assert_good_value(Product, :price, "0")
0
+      def assert_good_value(object_or_klass, attribute, value, error_message_to_avoid = //)
0
+        object = get_instance_of(object_or_klass)
0
         object.send("#{attribute}=", value)
0
         object.valid?
0
         assert_does_not_contain(object.errors.on(attribute), error_message_to_avoid, "when set to #{value.inspect}")
0
@@ -194,9 +205,20 @@ module ThoughtBot # :nodoc:
0
       # <tt>value</tt> by making sure the <tt>error_message_to_expect</tt> is
0
       # contained within the list of errors for that attribute.
0
       #
0
-      #   assert_bad_value(User.new, :email, "invalid") #=> passes
0
-      #   assert_bad_value(User.new, :ssn, "123", /length/) #=> passes
0
-      def assert_bad_value(object, attribute, value, error_message_to_expect = /invalid/)
0
+      #   assert_bad_value(User.new, :email, "invalid")
0
+      #   assert_bad_value(User.new, :ssn, "123", /length/)
0
+      #
0
+      # If a class is passed as the first argument, a new object will be
0
+      # instantiated before the assertion.  If an instance variable exists with
0
+      # the same name as the class (underscored), that object will be used
0
+      # instead.
0
+      #
0
+      #   assert_bad_value(User, :email, "invalid")
0
+      #
0
+      #   @product = Product.new(:tangible => true)
0
+      #   assert_bad_value(Product, :price, "0")
0
+      def assert_bad_value(object_or_klass, attribute, value, error_message_to_expect = /invalid/)
0
+        object = get_instance_of(object_or_klass)
0
         object.send("#{attribute}=", value)
0
         assert !object.valid?, "#{object.class} allowed #{value.inspect} as a value for #{attribute}"
0
         assert object.errors.on(attribute), "There are no errors on #{attribute} after being set to #{value.inspect}"
0
@@ -206,6 +228,17 @@ module ThoughtBot # :nodoc:
0
       def pretty_error_messages(obj)
0
         obj.errors.map { |a, m| "#{a} #{m} (#{obj.send(a).inspect})" }
0
       end
0
+
0
+      private
0
+
0
+      def get_instance_of(object_or_klass)
0
+        if object_or_klass.is_a?(Class)
0
+          klass = object_or_klass
0
+          instance_variable_get("@#{klass.to_s.underscore}") || klass.new
0
+        else
0
+          object_or_klass
0
+        end
0
+      end
0
     end
0
   end
0
 end

0
@@ -129,6 +129,20 @@ class HelpersTest < Test::Unit::TestCase # :nodoc:
0
         assert_good_value User.new, :ssn, "x", /length/
0
       end
0
     end
0
+
0
+    should "accept a class as the first argument" do
0
+      assert_good_value User, :email, "good@example.com"
0
+    end
0
+
0
+    context "with an instance variable" do
0
+      setup do
0
+        @product = Product.new(:tangible => true)
0
+      end
0
+
0
+      should "use that instance variable" do
0
+        assert_good_value Product, :price, "9999", /included/
0
+      end
0
+    end
0
   end
0
 
0
   context "assert_bad_value" do
0
@@ -151,5 +165,19 @@ class HelpersTest < Test::Unit::TestCase # :nodoc:
0
         assert_bad_value User.new, :ssn, "xxxxxxxxx", /length/
0
       end
0
     end
0
+
0
+    should "accept a class as the first argument" do
0
+      assert_bad_value User, :email, "bad"
0
+    end
0
+
0
+    context "with an instance variable" do
0
+      setup do
0
+        @product = Product.new(:tangible => true)
0
+      end
0
+
0
+      should "use that instance variable" do
0
+        assert_bad_value Product, :price, "0", /included/
0
+      end
0
+    end
0
   end
0
 end