Prefer assert_not over refute

actionpack/test/dispatch/routing/route_set_test.rb

@@ -24,7 +24,7 @@ def call(env)
           get 'foo', to: SimpleApp.new('foo#index')
         end
 
-        refute empty?
+        assert_not empty?
       end
 
       test "url helpers are added when route is added" do

actionpack/test/journey/routes_test.rb

@@ -14,7 +14,7 @@ def test_clear
         requirements = { :hello => /world/ }
 
         routes.add_route nil, path, requirements, {:id => nil}, {}
-        refute routes.empty?
+        assert_not routes.empty?
         assert_equal 1, routes.length
 
         routes.clear