macros.rb in thoughtbot-shoulda-2.10.2

- old
+ new
@@ -1,72 +1,132 @@
 require 'shoulda/private_helpers'
 
 module Shoulda # :nodoc:
   module Macros
     # Macro that creates a test asserting a change between the return value
-    # of an expression that is run before and after the current setup block
+    # of a block that is run before and after the current setup block
     # is run. This is similar to Active Support's <tt>assert_difference</tt>
     # assertion, but supports more than just numeric values.  See also
     # should_not_change.
     #
+    # The passed description will be used when generating the test name and failure messages.
+    #
     # Example:
     #
     #   context "Creating a post" do
     #     setup { Post.create }
-    #     should_change "Post.count", :by => 1
+    #     should_change("the number of posts", :by => 1) { Post.count }
     #   end
     #
     # As shown in this example, the <tt>:by</tt> option expects a numeric
     # difference between the before and after values of the expression.  You
     # may also specify <tt>:from</tt> and <tt>:to</tt> options:
     #
-    #   should_change "Post.count", :from => 0, :to => 1
-    #   should_change "@post.title", :from => "old", :to => "new"
+    #   should_change("the number of posts", :from => 0, :to => 1) { Post.count }
+    #   should_change("the post title", :from => "old", :to => "new") { @post.title }
     #
     # Combinations of <tt>:by</tt>, <tt>:from</tt>, and <tt>:to</tt> are allowed:
     #
-    #   should_change "@post.title"                # => assert the value changed in some way
-    #   should_change "@post.title", :from => "old" # => assert the value changed to anything other than "old"
-    #   should_change "@post.title", :to   => "new" # => assert the value changed from anything other than "new"
-    def should_change(expression, options = {})
+    #   # Assert the value changed in some way:
+    #   should_change("the post title") { @post.title }
+    #
+    #   # Assert the value changed to anything other than "old:"
+    #   should_change("the post title", :from => "old") { @post.title }
+    #
+    #   # Assert the value changed to "new:"
+    #   should_change("the post title", :to => "new") { @post.title }
+    def should_change(description, options = {}, &block)
       by, from, to = get_options!([options], :by, :from, :to)
-      stmt = "change #{expression.inspect}"
+      stmt = "change #{description}"
       stmt << " from #{from.inspect}" if from
       stmt << " to #{to.inspect}" if to
       stmt << " by #{by.inspect}" if by
 
-      expression_eval = lambda { eval(expression) }
-      before = lambda { @_before_should_change = expression_eval.bind(self).call }
+      if block_given?
+        code = block
+      else
+        warn "[DEPRECATION] should_change(expression, options) is deprecated. " <<
+             "Use should_change(description, options) { code } instead."
+        code = lambda { eval(description) }
+      end
+      before = lambda { @_before_should_change = code.bind(self).call }
       should stmt, :before => before do
         old_value = @_before_should_change
-        new_value = expression_eval.bind(self).call
-        assert_operator from, :===, old_value, "#{expression.inspect} did not originally match #{from.inspect}" if from
-        assert_not_equal old_value, new_value, "#{expression.inspect} did not change" unless by == 0
-        assert_operator to, :===, new_value, "#{expression.inspect} was not changed to match #{to.inspect}" if to
+        new_value = code.bind(self).call
+        assert_operator from, :===, old_value, "#{description} did not originally match #{from.inspect}" if from
+        assert_not_equal old_value, new_value, "#{description} did not change" unless by == 0
+        assert_operator to, :===, new_value, "#{description} was not changed to match #{to.inspect}" if to
         assert_equal old_value + by, new_value if by
       end
     end
 
     # Macro that creates a test asserting no change between the return value
-    # of an expression that is run before and after the current setup block
+    # of a block that is run before and after the current setup block
     # is run. This is the logical opposite of should_change.
     #
+    # The passed description will be used when generating the test name and failure message.
+    #
     # Example:
     #
     #   context "Updating a post" do
     #     setup { @post.update_attributes(:title => "new") }
-    #     should_not_change "Post.count"
+    #     should_not_change("the number of posts") { Post.count }
     #   end
-    def should_not_change(expression)
-      expression_eval = lambda { eval(expression) }
-      before = lambda { @_before_should_not_change = expression_eval.bind(self).call }
-      should "not change #{expression.inspect}", :before => before do
-        new_value = expression_eval.bind(self).call
-        assert_equal @_before_should_not_change, new_value, "#{expression.inspect} changed"
+    def should_not_change(description, &block)
+      if block_given?
+        code = block
+      else
+        warn "[DEPRECATION] should_not_change(expression) is deprecated. " <<
+             "Use should_not_change(description) { code } instead."
+        code = lambda { eval(description) }
       end
+      before = lambda { @_before_should_not_change = code.bind(self).call }
+      should "not change #{description}", :before => before do
+        new_value = code.bind(self).call
+        assert_equal @_before_should_not_change, new_value, "#{description} changed"
+      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
 