add a test on application layouts viewport meta tag

Author: jean-francois-labbe

railties/test/application/rake_test.rb

@@ -182,7 +182,7 @@ class Hello
     end
 
     def test_code_statistics
-      assert_match "Code LOC: 61     Test LOC: 3     Code to Test Ratio: 1:0.0",
+      assert_match "Code LOC: 62     Test LOC: 3     Code to Test Ratio: 1:0.0",
         rails("stats")
     end
 

railties/test/generators/app_generator_test.rb

@@ -551,6 +551,14 @@ def test_does_not_generate_system_test_files_if_skip_system_test_is_given
     end
   end
 
+  def test_viewport_meta_tag_is_present
+    run_generator [destination_root]
+
+    assert_file "app/views/layouts/application.html.erb" do |contents|
+      assert_match(/<meta name="viewport"/, contents)
+    end
+  end
+
   def test_javascript_is_skipped_if_required
     run_generator [destination_root, "--skip-javascript"]