Honestly, that is weird. I wouldn't expect an intro course to go into a lot of depth on testing or even necessarily show how to use a test framework, but I'd expect them to at least have "printf style" unit tests.

But lol, yeah, tests usually take far longer to write than the actual change I made. A one line change might need a hundred lines of test code. And if you're testing something that doesn't already have a similar test that you can start off from, programming the test setup can sometimes take some time. Depends a lot on what your code does, but sometimes you have to setup a whole fake database and a hierarchy of resources with a mixture of real objects with stubs.