Don't mark this test class as implementing the interface.
It doesn't correctly implement it, that's sort of the point of this test.
diff --git a/tests/hazmat/primitives/test_ec.py b/tests/hazmat/primitives/test_ec.py
index e6a9146..6aea58a 100644
--- a/tests/hazmat/primitives/test_ec.py
+++ b/tests/hazmat/primitives/test_ec.py
@@ -71,7 +71,6 @@
algorithm = None
-@utils.register_interface(EllipticCurveBackend)
class DeprecatedDummyECBackend(object):
def elliptic_curve_private_key_from_numbers(self, numbers):
return b"private_key"