Currently make spends a significant amount of time on test/test_*_tests.o, even on a modern iMac this is annoyingly slow.
This causes me to often build with --disable-tests, and then run ./configure again when I do want to run the unit test suite. So I don't run the unit test suite less often than I should (the functional test suite doesn't have this issue).
It would be better if the tests are compiled as part of make check.