kunit: tool: Do not error on tests without test plans

The (K)TAP spec encourages test output to begin with a 'test plan': a
count of the number of tests being run of the form:
1..n

However, some test suites might not know the number of subtests in
advance (for example, KUnit's parameterised tests use a generator
function). In this case, it's not possible to print the test plan in
advance.

kunit_tool already parses test output which doesn't contain a plan, but
reports an error. Since we want to use nested subtests with KUnit
paramterised tests, remove this error.
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

@@ -340,8 +340,8 @@ def parse_test_plan(lines: LineStream, test: Test) -> bool:
 	"""
 	Parses test plan line and stores the expected number of subtests in
 	test object. Reports an error if expected count is 0.
-	Returns False and reports missing test plan error if fails to parse
-	test plan.
+	Returns False and sets expected_count to None if there is no valid test
+	plan.
 
 	Accepted format:
 	- '1..[number of subtests]'
@@ -356,7 +356,6 @@ def parse_test_plan(lines: LineStream, test: Test) -> bool:
 	match = TEST_PLAN.match(lines.peek())
 	if not match:
 		test.expected_count = None
-		test.add_error('missing plan line!')
 		return False
 	test.log.append(lines.pop())
 	expected_count = int(match.group(1))

tools/testing/kunit/kunit_tool_test.py

@@ -191,7 +191,10 @@ class KUnitParserTest(unittest.TestCase):
 			result = kunit_parser.parse_run_tests(
 				kunit_parser.extract_tap_lines(
 				file.readlines()))
-		self.assertEqual(2, result.test.counts.errors)
+		# A missing test plan is not an error.
+		self.assertEqual(0, result.test.counts.errors)
+		# All tests should be accounted for.
+		self.assertEqual(10, result.test.counts.total())
 		self.assertEqual(
 			kunit_parser.TestStatus.SUCCESS,
 			result.status)