kunit: tool: Report an error if any test has no subtests

It's possible for a test to have a subtest header, but zero valid
subtests. We used to error on this if the test plan had no subtests
listed, but it's possible to have subtests without a test plan (indeed,
this is how parameterised tests work).

Tests with 0 subtests now have the result NO_TESTS, and will report an
error (which does not halt test execution, but is printed in a scary red
colour and is noted in the results summary).

Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/kunit/kunit_parser.py

@@ -360,9 +360,6 @@ def parse_test_plan(lines: LineStream, test: Test) -> bool:
 	test.log.append(lines.pop())
 	expected_count = int(match.group(1))
 	test.expected_count = expected_count
-	if expected_count == 0:
-		test.status = TestStatus.NO_TESTS
-		test.add_error('0 tests run!')
 	return True
 
 TEST_RESULT = re.compile(r'^(ok|not ok) ([0-9]+) (- )?([^#]*)( # .*)?$')
@@ -589,6 +586,8 @@ def format_test_result(test: Test) -> str:
 		return (green('[PASSED] ') + test.name)
 	elif test.status == TestStatus.SKIPPED:
 		return (yellow('[SKIPPED] ') + test.name)
+	elif test.status == TestStatus.NO_TESTS:
+		return (yellow('[NO TESTS RUN] ') + test.name)
 	elif test.status == TestStatus.TEST_CRASHED:
 		print_log(test.log)
 		return (red('[CRASHED] ') + test.name)
@@ -731,6 +730,7 @@ def parse_test(lines: LineStream, expected_num: int, log: List[str]) -> Test:
 		# test plan
 		test.name = "main"
 		parse_test_plan(lines, test)
+		parent_test = True
 	else:
 		# If KTAP/TAP header is not found, test must be subtest
 		# header or test result line so parse attempt to parser
@@ -744,7 +744,7 @@ def parse_test(lines: LineStream, expected_num: int, log: List[str]) -> Test:
 	expected_count = test.expected_count
 	subtests = []
 	test_num = 1
-	while expected_count is None or test_num <= expected_count:
+	while parent_test and (expected_count is None or test_num <= expected_count):
 		# Loop to parse any subtests.
 		# Break after parsing expected number of tests or
 		# if expected number of tests is unknown break when test
@@ -779,9 +779,15 @@ def parse_test(lines: LineStream, expected_num: int, log: List[str]) -> Test:
 			parse_test_result(lines, test, expected_num)
 		else:
 			test.add_error('missing subtest result line!')
+
+	# Check for there being no tests
+	if parent_test and len(subtests) == 0:
+		test.status = TestStatus.NO_TESTS
+		test.add_error('0 tests run!')
+
 	# Add statuses to TestCounts attribute in Test object
 	bubble_up_test_results(test)
-	if parent_test:
+	if parent_test and not main:
 		# If test has subtests and is not the main test object, print
 		# footer.
 		print_test_footer(test)

tools/testing/kunit/kunit_tool_test.py

@@ -209,6 +209,18 @@ class KUnitParserTest(unittest.TestCase):
 			kunit_parser.TestStatus.NO_TESTS,
 			result.status)
 
+	def test_no_tests_no_plan(self):
+		no_plan_log = test_data_path('test_is_test_passed-no_tests_no_plan.log')
+		with open(no_plan_log) as file:
+			result = kunit_parser.parse_run_tests(
+				kunit_parser.extract_tap_lines(file.readlines()))
+		self.assertEqual(0, len(result.test.subtests[0].subtests[0].subtests))
+		self.assertEqual(
+			kunit_parser.TestStatus.NO_TESTS,
+			result.test.subtests[0].subtests[0].status)
+		self.assertEqual(1, result.test.counts.errors)
+
+
 	def test_no_kunit_output(self):
 		crash_log = test_data_path('test_insufficient_memory.log')
 		print_mock = mock.patch('builtins.print').start()

tools/testing/kunit/test_data/test_is_test_passed-no_tests_no_plan.log

@@ -0,0 +1,7 @@
+TAP version 14
+1..1
+  # Subtest: suite
+  1..1
+    # Subtest: case
+  ok 1 - case # SKIP
+ok 1 - suite