kunit: tool: don't include KTAP headers and the like in the test log

We print the "test log" on failure.
This is meant to be all the kernel output that happened during the test.

But we also include the special KTAP lines in it, which are often
redundant.

E.g. we include the "not ok" line in the log, right before we print
that the test case failed...
[13:51:48] Expected 2 + 1 == 2, but
[13:51:48] 2 + 1 == 3 (0x3)
[13:51:48] not ok 1 example_simple_test
[13:51:48] [FAILED] example_simple_test

More full example after this patch:
[13:51:48] =================== example (4 subtests) ===================
[13:51:48] # example_simple_test: initializing
[13:51:48] # example_simple_test: EXPECTATION FAILED at lib/kunit/kunit-example-test.c:29
[13:51:48] Expected 2 + 1 == 2, but
[13:51:48] 2 + 1 == 3 (0x3)
[13:51:48] [FAILED] example_simple_test

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

tools/testing/kunit/kunit_parser.py

@@ -295,7 +295,7 @@ def parse_ktap_header(lines: LineStream, test: Test) -> bool:
 		check_version(version_num, TAP_VERSIONS, 'TAP', test)
 	else:
 		return False
-	test.log.append(lines.pop())
+	lines.pop()
 	return True
 
 TEST_HEADER = re.compile(r'^# Subtest: (.*)$')
@@ -318,8 +318,8 @@ def parse_test_header(lines: LineStream, test: Test) -> bool:
 	match = TEST_HEADER.match(lines.peek())
 	if not match:
 		return False
-	test.log.append(lines.pop())
 	test.name = match.group(1)
+	lines.pop()
 	return True
 
 TEST_PLAN = re.compile(r'1\.\.([0-9]+)')
@@ -345,9 +345,9 @@ def parse_test_plan(lines: LineStream, test: Test) -> bool:
 	if not match:
 		test.expected_count = None
 		return False
-	test.log.append(lines.pop())
 	expected_count = int(match.group(1))
 	test.expected_count = expected_count
+	lines.pop()
 	return True
 
 TEST_RESULT = re.compile(r'^(ok|not ok) ([0-9]+) (- )?([^#]*)( # .*)?$')
@@ -409,7 +409,7 @@ def parse_test_result(lines: LineStream, test: Test,
 	# Check if line matches test result line format
 	if not match:
 		return False
-	test.log.append(lines.pop())
+	lines.pop()
 
 	# Set name of test object
 	if skip_match:

tools/testing/kunit/kunit_tool_test.py

@@ -84,6 +84,10 @@ class KUnitParserTest(unittest.TestCase):
 		self.print_mock = mock.patch('kunit_printer.Printer.print').start()
 		self.addCleanup(mock.patch.stopall)
 
+	def noPrintCallContains(self, substr: str):
+		for call in self.print_mock.mock_calls:
+			self.assertNotIn(substr, call.args[0])
+
 	def assertContains(self, needle: str, haystack: kunit_parser.LineStream):
 		# Clone the iterator so we can print the contents on failure.
 		copy, backup = itertools.tee(haystack)
@@ -327,6 +331,19 @@ class KUnitParserTest(unittest.TestCase):
 			result = kunit_parser.parse_run_tests(file.readlines())
 		self.print_mock.assert_any_call(StrContains('suite (1 subtest)'))
 
+	def test_show_test_output_on_failure(self):
+		output = """
+		KTAP version 1
+		1..1
+		  Test output.
+		not ok 1 test1
+		"""
+		result = kunit_parser.parse_run_tests(output.splitlines())
+		self.assertEqual(kunit_parser.TestStatus.FAILURE, result.status)
+
+		self.print_mock.assert_any_call(StrContains('Test output.'))
+		self.noPrintCallContains('not ok 1 test1')
+
 def line_stream_from_strs(strs: Iterable[str]) -> kunit_parser.LineStream:
 	return kunit_parser.LineStream(enumerate(strs, start=1))