"make test" used to abort after the first test failure. That was
partly intentional: if the simple tests already fail (for example,
because of a syntax error), then there is no point in continuing to
test.

However, it also makes it harder to find all errors in a CI system
when the errors are unrelated (first error shows up, gets fixed, next
error shows up, etc.).

Now "make test" still aborts early, but "make -k test" is used in the
CI and will run all individual tests because they are split up into
different targets.