Fix assert_template for files.

The test was not failing for `assert_template file: nil` when a file
has been rendered.

1 files changed, 9 insertions, 0 deletions

diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index eb5d824cbc..152420a54c 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -91,6 +91,13 @@ module ActionController
     #   # assert that no partials were rendered
     #   assert_template partial: false
     #
+    #   # assert that a file was rendered
+    #   assert_template file: "README.rdoc"
+    #
+    #   # assert that no file was rendered
+    #   assert_template file: nil
+    #   assert_template file: false
+    #
     # In a view test case, you can also assert that specific locals are passed
     # to partials:
     #
@@ -140,6 +147,8 @@ module ActionController
 
         if options[:file]
           assert_includes @_files.keys, options[:file]
+        elsif options.key?(:file)
+          assert @_files.blank?, "expected no files but #{@_files.keys} was rendered"
         end
 
         if expected_partial = options[:partial]