In ActionView::TestCase::Behavior, assign variables right before

rendering the view.

- Previously, _assigns were locked down the first time _view was
  referenced.

[rails#4931 state:resolved]

actionpack/lib/action_view/base.rb

@@ -204,8 +204,12 @@ def self.process_view_paths(value)
         value.dup : ActionView::PathSet.new(Array.wrap(value))
     end
 
+    def assign(new_assigns) # :nodoc:
+      self.assigns = new_assigns.each { |key, value| instance_variable_set("@#{key}", value) }
+    end
+
     def initialize(lookup_context = nil, assigns_for_first_render = {}, controller = nil, formats = nil) #:nodoc:
-      self.assigns = assigns_for_first_render.each { |key, value| instance_variable_set("@#{key}", value) }
+      assign(assigns_for_first_render)
       self.helpers = self.class.helpers || Module.new
 
       if @_controller = controller

actionpack/lib/action_view/test_case.rb

@@ -99,6 +99,7 @@ def config
       end
 
       def render(options = {}, local_assigns = {}, &block)
+        _view.assign(_assigns)
         @rendered << output = _view.render(options, local_assigns, &block)
         output
       end
@@ -147,7 +148,7 @@ def _render_partial(options)
 
       def _view
         @_view ||= begin
-                     view = ActionView::Base.new(ActionController::Base.view_paths, _assigns, @controller)
+                     view = ActionView::Base.new(ActionController::Base.view_paths, {}, @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"

actionpack/test/template/test_case_test.rb

@@ -200,6 +200,15 @@ def render_from_helper
       assert_match /Hello: EloyHello: Manfred/, render(:file => 'test/list')
     end
 
+    test "is able to render partials from templates and also use instance variables after _view has been referenced" do
+      @controller.controller_path = "test"
+
+      _view
+
+      @customers = [stub(:name => 'Eloy'), stub(:name => 'Manfred')]
+      assert_match /Hello: EloyHello: Manfred/, render(:file => 'test/list')
+    end
+
   end
 
   class AssertionsTest < ActionView::TestCase