Add a test for empty path segments

src/cowboy_dispatcher.erl

@@ -215,6 +215,8 @@ split_path_test_() ->
 		{<<"?">>, [], <<"">>, <<"">>},
 		{<<"???">>, [], <<"">>, <<"??">>},
 		{<<"/">>, [], <<"/">>, <<"">>},
+		{<<"/extend//cowboy">>, [<<"extend">>, <<>>, <<"cowboy">>],
+			<<"/extend//cowboy">>, <<>>},
 		{<<"/users">>, [<<"users">>], <<"/users">>, <<"">>},
 		{<<"/users?">>, [<<"users">>], <<"/users">>, <<"">>},
 		{<<"/users?a">>, [<<"users">>], <<"/users">>, <<"a">>},