Fix JWK.from_json #130

import_keyset no longer returns self.

jwcrypto/jwk.py

@@ -441,7 +441,8 @@ def from_json(cls, key):
             jkey = json_decode(key)
         except Exception as e:  # pylint: disable=broad-except
             raise InvalidJWKValue(e)
-        return obj.import_key(**jkey)
+        obj.import_key(**jkey)
+        return obj
 
     def export(self, private_key=True):
         """Exports the key in the standard JSON format.
@@ -854,16 +855,15 @@ def import_keyset(self, keyset):
             else:
                 self[k] = v
 
-        return self
-
     @classmethod
     def from_json(cls, keyset):
         """Creates a RFC 7517 keyset from the standard JSON format.
 
         :param keyset: The RFC 7517 representation of a JOSE Keyset.
         """
         obj = cls()
-        return obj.import_keyset(keyset)
+        obj.import_keyset(keyset)
+        return obj
 
     def get_key(self, kid):
         """Gets a key from the set.

jwcrypto/tests.py

@@ -311,11 +311,17 @@ def test_import_pyca_keys(self):
         self.assertRaises(jwk.InvalidJWKValue,
                           jwk.JWK.from_pyca, dict())
 
+    def test_jwk_from_json(self):
+        k = jwk.JWK.generate(kty='oct', size=256)
+        y = jwk.JWK.from_json(k.export())
+        self.assertEqual(k.export(), y.export())
+
     def test_jwkset(self):
         k = jwk.JWK(**RSAPrivateKey)
         ks = jwk.JWKSet()
         ks.add(k)
-        ks2 = jwk.JWKSet().import_keyset(ks.export())
+        ks2 = jwk.JWKSet()
+        ks2.import_keyset(ks.export())
         self.assertEqual(len(ks), len(ks2))
         self.assertEqual(len(ks), 1)
         k1 = ks.get_key(RSAPrivateKey['kid'])