try a package structure

__init__.py

+#!/usr/bin/env python3
+
+from .core import Eins

core.py

@@ -6,8 +6,8 @@ from functools import wraps
 
 import paho.mqtt.client as mqtt
 
-from command import Command
-from helpers import *
+from .command import Command
+from .helpers import *
 
 class Eins:
     def __init__(self,

test_core.py → tests/test_core.py

 #!/usr/bin/env python3
 
-from core import *
+from eins import Eins
 
 eins = Eins()
 

test_manager.py → tests/test_manager.py

 #!/usr/bin/env python3
 
-from manager import *
+from eins import Manager
 
 with Manager() as eins:
     pass