island: Simplify UserCreds constructor by removing defaults

The default values were only really used by the test code. We can
simplify the Usercreds's interface and test code by removing
functionality (read: complication) we don't really need.

monkey/monkey_island/cc/environment/user_creds.py

@@ -8,7 +8,7 @@
 
 
 class UserCreds:
-    def __init__(self, username="", password_hash=""):
+    def __init__(self, username, password_hash):
         self.username = username
         self.password_hash = password_hash
 

monkey/tests/monkey_island/cc/environment/test_environment.py

@@ -20,6 +20,8 @@
 STANDARD_WITH_CREDENTIALS = None
 STANDARD_ENV = None
 
+EMPTY_CREDS = UserCreds("", "")
+
 
 # This fixture is a dirty hack that can be removed once these tests are converted from
 # unittest to pytest. Instead, the appropriate fixtures from conftest.py can be used.
@@ -67,7 +69,7 @@ def get_server_config_file_path_test_version():
 class TestEnvironment(TestCase):
     class EnvironmentCredentialsNotRequired(Environment):
         def __init__(self):
-            config = StubEnvironmentConfig("test", "test", UserCreds())
+            config = StubEnvironmentConfig("test", "test", EMPTY_CREDS)
             super().__init__(config)
 
         _credentials_required = False
@@ -77,7 +79,7 @@ def get_auth_users(self):
 
     class EnvironmentCredentialsRequired(Environment):
         def __init__(self):
-            config = StubEnvironmentConfig("test", "test", UserCreds())
+            config = StubEnvironmentConfig("test", "test", EMPTY_CREDS)
             super().__init__(config)
 
         _credentials_required = True
@@ -101,7 +103,7 @@ def test_try_add_user(self):
         credentials = UserCreds(username="test", password_hash="1231234")
         env.try_add_user(credentials)
 
-        credentials = UserCreds(username="test")
+        credentials = UserCreds(username="test", password_hash="")
         with self.assertRaises(InvalidRegistrationCredentialsError):
             env.try_add_user(credentials)
 

monkey/tests/monkey_island/cc/environment/test_user_creds.py

@@ -6,7 +6,7 @@
 
 
 def test_to_dict_empty_creds():
-    user_creds = UserCreds()
+    user_creds = UserCreds("", "")
     assert user_creds.to_dict() == {}
 
 
@@ -23,14 +23,6 @@ def test_to_auth_user_full_credentials():
     assert auth_user.secret == "abc1231234"
 
 
-def test_to_auth_user_username_only():
-    user_creds = UserCreds(username="Test")
-    auth_user = user_creds.to_auth_user()
-    assert auth_user.id == 1
-    assert auth_user.username == "Test"
-    assert auth_user.secret == ""
-
-
 def test_get_from_cleartext(monkeypatch):
     monkeypatch.setattr(bcrypt, "gensalt", lambda: TEST_SALT)