fix tests

tests/test_keys.py

@@ -0,0 +1,7 @@
+from coincurve import PrivateKey, PublicKey
+from .samples import PRIVATE_KEY_BYTES, PUBLIC_KEY_COMPRESSED
+
+
+class TestPrivateKey:
+    def test_public_key(self):
+        assert PrivateKey(PRIVATE_KEY_BYTES).public_key.format() == PUBLIC_KEY_COMPRESSED