The generated test driver can treat unimplemented tests in two ways: either count them all as failed (this is useful to see which tests are still left to implement) or as passed (to sort out unimplemented ones from those actually failing).
The test driver accepts a switch to specify this behavior: –stub-default=val, where val is either "pass" or "fail" (exactly as for gnattest).
The default behavior of the test driver is set with the same switch as passed to gnattest when generating the test driver.
Passing it to the driver generated on the first example:
makes both tests pass, even the unimplemented one.