1 files changed, 4 insertions, 1 deletions
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index cd92962dc3..9a77f179d3 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -67,7 +67,8 @@ module ActionController
 
     def reset_template_assertion
       RENDER_TEMPLATE_INSTANCE_VARIABLES.each do |instance_variable|
-        instance_variable_get("@_#{instance_variable}").clear
+        ivar = instance_variable_get("@_#{instance_variable}")
+        ivar.clear if ivar
       end
     end
 
@@ -145,6 +146,8 @@ module ActionController
             assert(@_layouts.keys.any? {|l| l =~ expected_layout }, msg)
           when nil, false
             assert(@_layouts.empty?, msg)
+          else
+            raise ArgumentError, "assert_template only accepts a String, Symbol, Regexp, nil or false for :layout"
           end
         end