Cover is run on 2.7, so mark 3-only lines as no cover

acme/acme/crypto_util_test.py

@@ -18,7 +18,7 @@ from acme.magic_typing import List # pylint: disable=unused-import, no-name-in-m
 
 # turns all ResourceWarnings into errors for this module
 if six.PY3:
-    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning")
+    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning") # pragma: no cover
 
 
 class SSLSocketAndProbeSNITest(unittest.TestCase):

acme/acme/messages_test.py

@@ -17,7 +17,7 @@ KEY = test_util.load_rsa_private_key('rsa512_key.pem')
 
 # turns all ResourceWarnings into errors for this module
 if six.PY3:
-    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning")
+    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning") # pragma: no cover
 
 
 class ErrorTest(unittest.TestCase):

acme/acme/standalone_test.py

@@ -23,7 +23,7 @@ from acme.magic_typing import Set # pylint: disable=unused-import, no-name-in-mo
 
 # turns all ResourceWarnings into errors for this module
 if six.PY3:
-    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning")
+    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning") # pragma: no cover
 
 
 class TLSServerTest(unittest.TestCase):

acme/acme/util_test.py

@@ -6,7 +6,7 @@ import six
 
 # turns all ResourceWarnings into errors for this module
 if six.PY3:
-    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning")
+    pytestmark = pytest.mark.filterwarnings("ignore::ResourceWarning") # pragma: no cover
 
 
 class MapKeysTest(unittest.TestCase):