Add support for specifying locals in view tests with assert template

Closes rails#4927.

actionpack/lib/action_controller/test_case.rb

@@ -40,7 +40,7 @@ def teardown_subscriptions
       ActiveSupport::Notifications.unsubscribe("!render_template.action_view")
     end
 
-    # Asserts that the request was rendered with the appropriate template file or partials
+    # Asserts that the request was rendered with the appropriate template file or partials.
     #
     # ==== Examples
     #
@@ -53,6 +53,12 @@ def teardown_subscriptions
     #   # assert that no partials were rendered
     #   assert_template :partial => false
     #
+    # In a view test case, you can also assert that specific locals are passed
+    # to partials:
+    #
+    #   # assert that the "_customer" partial was rendered with a specific object
+    #   assert_template :partial => '_customer', :locals => { :customer => @customer }
+    #
     def assert_template(options = {}, message = nil)
       validate_request!
 
@@ -72,9 +78,13 @@ def assert_template(options = {}, message = nil)
         end
       when Hash
         if expected_partial = options[:partial]
-          if expected_count = options[:count]
+          if expected_locals = options[:locals]
+            actual_locals = @locals[expected_partial.to_s.sub(/^_/,'')]
+            expected_locals.each_pair do |k,v|
+              assert_equal(v, actual_locals[k])
+            end
+          elsif expected_count = options[:count]
             actual_count = @partials[expected_partial]
-            # actual_count = found.nil? ? 0 : found[1]
             msg = build_message(message,
                     "expecting ? to be rendered ? time(s) but rendered ? time(s)",
                      expected_partial, expected_count, actual_count)

actionpack/lib/action_view/test_case.rb

@@ -103,6 +103,10 @@ def render(options = {}, local_assigns = {}, &block)
         output
       end
 
+      def locals
+        @locals ||= {}
+      end
+
       included do
         setup :setup_with_controller
       end
@@ -132,12 +136,23 @@ def make_test_case_available_to_view!
         end
       end
 
+      module Locals
+        attr_accessor :locals
+
+        def _render_partial(options)
+          locals[options[:partial]] = options[:locals]
+          super(options)
+        end
+      end
+
       def _view
         @_view ||= begin
                      view = ActionView::Base.new(ActionController::Base.view_paths, _assigns, @controller)
                      view.singleton_class.send :include, _helpers
                      view.singleton_class.send :include, @controller._router.url_helpers
                      view.singleton_class.send :delegate, :alert, :notice, :to => "request.flash"
+                     view.extend(Locals)
+                     view.locals = self.locals
                      view.output_buffer = self.output_buffer
                      view
                    end

actionpack/test/template/test_case_test.rb

@@ -220,10 +220,24 @@ def render_from_helper
   end
 
   class RenderTemplateTest < ActionView::TestCase
-    test "render template" do
+    test "render template supports specifying partials" do
       controller.controller_path = "test"
       render(:template => "test/calling_partial_with_layout")
-      assert_template "partial_for_use_in_layout"
+      assert_template :partial => "_partial_for_use_in_layout"
+    end
+
+    test "render template supports specifying locals (passing)" do
+      controller.controller_path = "test"
+      render(:template => "test/calling_partial_with_layout")
+      assert_template :partial => "_partial_for_use_in_layout", :locals => { :name => "David" }
+    end
+
+    test "render template supports specifying locals (failing)" do
+      controller.controller_path = "test"
+      render(:template => "test/calling_partial_with_layout")
+      assert_raise Test::Unit::AssertionFailedError, /Somebody else.*David/m do
+        assert_template :partial => "_partial_for_use_in_layout", :locals => { :name => "Somebody Else" }
+      end
     end
   end
 end