[test] Exit with an error if no tests are run.

[rupprecht]

Summary

If the test suite is misconfigured when it's run (a bad regexp, wrong test directory, etc.), the test suite may not discover any tests. When this happens, the test runner exits happily because no tests failed:

Ran 0 tests in 0.000s
RESULT: PASSED (0 passes, 0 failures, 0 errors, 0 skipped, 0 expected failures, 0 unexpected successes)

Change this to return an error so the misconfiguration can be more easily detected. Verified that lldb-dotest -p TestDoesNotExist.py successfully fails.

[JDevlieghere]

LGTM

lldb/packages/Python/lldbsuite/test/dotest.py

1043

Maybe did not discover any (matching) tests to make it clear that this might be the result of user input?

[MaskRay]

lldb/packages/Python/lldbsuite/test/dotest.py

1043

sys.stderr.write or print(..., file=sys.stderr) (which appends a newline)

Trailing full stops are not recommended for error messages if the project does not already have the convention http://llvm.org/docs/CodingStandards.html#error-and-warning-messages

Looking around, several messages do not have a full stop.

[JDevlieghere]

lldb/packages/Python/lldbsuite/test/dotest.py

1043

Let's use logging.error like the other error messages if we want this to go to stderr.

[rupprecht]

• Use logging.error
• Remove trailing stop
• Edit message to indicate that matching tests weren't found (user error)

[JDevlieghere]

Thanks!

[rupprecht]

Thanks for the quick review!

I have a few more boring changes coming up, but hopefully some interesting ones after that.

lldb/packages/Python/lldbsuite/test/dotest.py

def run_suite():
     # First, write out the number of collected test cases.
     if configuration.verbose:
         sys.stderr.write(configuration.separator + "\n")
         sys.stderr.write(
             "Collected %d test%s\n\n" %
             (configuration.suite.countTestCases(),
              configuration.suite.countTestCases() != 1 and "s" or ""))
 
+    if configuration.suite.countTestCases() == 0:
+        print("error: did not discover any tests.")
+        exitTestSuite(1)
+
     # Invoke the test runner.
     if configuration.count == 1:
         result = unittest2.TextTestRunner(
             stream=sys.stderr,
             verbosity=configuration.verbose,
             resultclass=test_result.LLDBTestResult).run(
             configuration.suite)
     else: