Detect if running in Travis using PATH

Author: c0llab0rat0r

test/functional/conftest.py

@@ -55,9 +55,13 @@ def is_responsive() -> bool:
 	return address
 
 
+def _running_in_travis_ci() -> bool:
+	return '/home/travis/build' in os.getenv('PATH')
+
+
 @pytest.fixture(scope='session')
 def ipfs_service_auth() -> ty.Generator[ty.Tuple[str, str], None, None]:
-	if os.getenv('CI') != 'yes':
+	if not _running_in_travis_ci():
 		# Docker pull hits docker hub rate limits when running on Travis CI; avoiding the
 		# rate limit requires a Docker Hub account.
 		#