From 967b9fc67c8fbe5f96ecfb710b08993fed0f66da Mon Sep 17 00:00:00 2001
From: Matt Jankowski <mjankowski@thoughtbot.com>
Date: Sat, 20 Sep 2008 16:06:28 -0400
Subject: [PATCH] add an :equals option to should_assign_to which checks that
 the assigned instance variable is equal to the eval of the string passed to
 the option

---
 lib/shoulda/controller/macros.rb         | 18 +++++++++++++++---
 test/functional/posts_controller_test.rb |  5 ++++-
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/lib/shoulda/controller/macros.rb b/lib/shoulda/controller/macros.rb
index 8a4bc0c8..711cecbd 100644
--- a/lib/shoulda/controller/macros.rb
+++ b/lib/shoulda/controller/macros.rb
@@ -101,19 +101,31 @@ def should_not_set_the_flash
         #
         # Options:
         # * <tt>:class</tt> - The expected class of the instance variable being checked.
+        # * <tt>:equals</tt> - A string which is evaluated and compared for equality with
+        # the instance variable being checked.
         #
         # Example:
         #
         #   should_assign_to :user, :posts
         #   should_assign_to :user, :class => User
+        #   should_assign_to :user, :equals => '@user'
         def should_assign_to(*names)
           opts = names.extract_options!
           names.each do |name|
             test_name = "assign @#{name}"
-            test_name << " as #{opts[:class]}" if opts[:class]
+            test_name << " as class #{opts[:class]}" if opts[:class]
+            test_name << " which is equal to #{opts[:equals]}" if opts[:equals]
             should test_name do
-              assert assigns(name.to_sym), "The action isn't assigning to @#{name}"
-              assert_kind_of opts[:class], assigns(name.to_sym) if opts[:class]
+              assigned_value = assigns(name.to_sym)
+              assert assigned_value, "The action isn't assigning to @#{name}"
+              assert_kind_of opts[:class], assigned_value if opts[:class]
+              if opts[:equals]
+                instantiate_variables_from_assigns do
+                  expected_value = eval(opts[:equals], self.send(:binding), __FILE__, __LINE__)
+                  assert_equal expected_value, assigned_value,
+                  "Instance variable @#{name} expected to be #{expected_value} but was #{assigned_value}"
+                end
+              end
             end
           end
         end
diff --git a/test/functional/posts_controller_test.rb b/test/functional/posts_controller_test.rb
index 75b214e7..9e34b031 100644
--- a/test/functional/posts_controller_test.rb
+++ b/test/functional/posts_controller_test.rb
@@ -64,10 +64,13 @@ def setup
         get :index, :user_id => users(:first)
       end
       should_respond_with :success
-      should_assign_to :user, :class => User
+      should_assign_to :user, :class => User, :equals => 'users(:first)'
       should_fail do
         should_assign_to :user, :class => Post
       end
+      should_fail do
+        should_assign_to :user, :equals => 'posts(:first)'
+      end
       should_assign_to :posts
       should_not_assign_to :foo, :bar
     end