@hobovsky
I have defined that operator for my type and it still does not work.

Edit: it did not work because I had other mistakes in my code (mainly to do with const qualifiers of functions). Once my code started working I removed the operator<< definition and started getting errors connected it. Thank you for the suggestion.

You need to define operator << for your type. Otherwise, testing framework cannot stringify it to build an assertion message.

The same problem. My solution works locally using Cygwin Clang 8.0.1 but raises a similar error here.

1170050802 / 5262 is not an integer (and 27115 / 5262 isn't reducible) , so that can't be the lcm.