Added should_create and should_destroy [#190 state:resolved]

.gitignore

@@ -4,3 +4,4 @@ coverage
 .svn/
 pkg
 *.swp
+tags

lib/shoulda/macros.rb

@@ -65,8 +65,47 @@ module Shoulda # :nodoc:
       end
     end
 
+    # Macro that creates a test asserting that a record of the given class was
+    # created.
+    #
+    # Example:
+    #
+    #   context "creating a post" do
+    #     setup { Post.create(post_attributes) }
+    #     should_create :post
+    #   end
+    def should_create(class_name)
+      should_change_record_count_of(class_name, 1, 'create')
+    end
+
+    # Macro that creates a test asserting that a record of the given class was
+    # destroyed.
+    #
+    # Example:
+    #
+    #   context "destroying a post" do
+    #     setup { Post.first.destroy }
+    #     should_destroy :post
+    #   end
+    def should_destroy(class_name)
+      should_change_record_count_of(class_name, -1, 'destroy')
+    end
+
     private
 
+    def should_change_record_count_of(class_name, amount, action) # :nodoc:
+      klass = class_name.to_s.camelize.constantize
+      before = lambda do
+        @_before_change_record_count = klass.count
+      end
+      human_name = class_name.to_s.humanize.downcase
+      should "#{action} a #{human_name}", :before => before do
+        assert_equal @_before_change_record_count + amount,
+                     klass.count,
+                     "Expected to #{action} a #{human_name}"
+      end
+    end
+
     include Shoulda::Private
   end
 end

test/other/helpers_test.rb

@@ -238,4 +238,68 @@ class HelpersTest < Test::Unit::TestCase # :nodoc:
       end
     end
   end
+
+  context "given one treat exists and one post exists" do
+    setup do
+      Treat.create!
+      Post.create!(:title => 'title', :body => 'body', :user_id => 1)
+    end
+
+    teardown do
+      Treat.delete_all
+      Post.delete_all
+    end
+
+    context "creating a treat" do
+      setup do
+        Treat.create!
+      end
+
+      should_create :treat
+      should_fail do
+        should_create :post
+      end
+    end
+
+    context "creating a treat and a post" do
+      setup do
+        Treat.create!
+        Post.create!(:title => 'title 2', :body => 'body', :user_id => 1)
+      end
+
+      should_create :treat
+      should_create :post
+    end
+
+    context "destroying a treat" do
+      setup do
+        Treat.first.destroy
+      end
+
+      should_destroy :treat
+      should_fail do
+        should_destroy :post
+      end
+    end
+
+    context "destroying a treat and a post" do
+      setup do
+        Treat.first.destroy
+        Post.first.destroy
+      end
+
+      should_destroy :treat
+      should_destroy :post
+    end
+
+    context "doing nothing" do
+      should_fail do
+        should_create :treat
+      end
+
+      should_fail do
+        should_destroy :treat
+      end
+    end
+  end
 end