diff --git a/python/.devcontainer/Dockerfile b/python/.devcontainer/Dockerfile
index 7cf707e..eff9cf2 100644
--- a/python/.devcontainer/Dockerfile
+++ b/python/.devcontainer/Dockerfile
@@ -6,6 +6,8 @@ ARG USERNAME=vscode
 ARG USER_UID=1000
 ARG USER_GID=$USER_UID
 
+RUN pip install --no-cache-dir pytest black
+
 RUN groupadd --gid $USER_GID $USERNAME && useradd --uid $USER_UID --gid $USER_GID -m $USERNAME
 USER $USERNAME
 WORKDIR /workspace
diff --git a/python/.devcontainer/devcontainer.json b/python/.devcontainer/devcontainer.json
index ec8d953..5b115e6 100644
--- a/python/.devcontainer/devcontainer.json
+++ b/python/.devcontainer/devcontainer.json
@@ -1,19 +1,31 @@
 {
-  "name": "Python 3.11 Dev Container",
-  "dockerFile": "Dockerfile",
-  "mounts": [
-    "source=${localWorkspaceFolder},target=/workspace,type=bind"
-  ],
-  "settings": {
-    "python.linting.enabled": true,
-    "python.linting.pylintEnabled": true,
-    "python.formatting.provider": "black"
-  },
-  "extensions": [
-    "ms-python.python",
-    "ms-python.vscode-pylance"
-  ],
-  
-  "postCreateCommand": "pip install --upgrade pip && pip install pytest black",
-  "remoteUser": "vscode"
+    "name": "Python 3.11 Dev Container",
+    "image": "dev-test-image:latest",
+    //"dockerFile": "Dockerfile",
+    "mounts": [
+        "source=${localWorkspaceFolder},target=/workspace,type=bind"
+    ],
+    "remoteUser": "vscode",
+    
+    "customizations": {
+        "vscode": {
+            "settings": {
+                // Testing: Pytest-Erkennung aktivieren
+                "python.testing.pytestEnabled": true,
+                "python.testing.pytestArgs": [
+                    "." 
+                ],
+                
+                "python.linting.enabled": true,
+                "python.linting.pylintEnabled": true,
+                "python.formatting.provider": "black"
+            },
+            "extensions": [
+                "ms-python.python",
+                "ms-python.vscode-pylance"
+            ]
+        }
+    },
+
+    "postCreateCommand": "pip install --upgrade pip" 
 }
\ No newline at end of file
diff --git a/python/01_python_tooling/__pycache__/sum_calculator.cpython-311.pyc b/python/01_python_tooling/__pycache__/sum_calculator.cpython-311.pyc
new file mode 100644
index 0000000..ced54c8
Binary files /dev/null and b/python/01_python_tooling/__pycache__/sum_calculator.cpython-311.pyc differ
diff --git a/python/01_python_tooling/__pycache__/test_sum_calculator.cpython-311-pytest-9.0.2.pyc b/python/01_python_tooling/__pycache__/test_sum_calculator.cpython-311-pytest-9.0.2.pyc
new file mode 100644
index 0000000..e12db6b
Binary files /dev/null and b/python/01_python_tooling/__pycache__/test_sum_calculator.cpython-311-pytest-9.0.2.pyc differ
diff --git a/python/01_python_tooling/test_sum_calculator.py b/python/01_python_tooling/test_sum_calculator.py
deleted file mode 100644
index 3d06087..0000000
--- a/python/01_python_tooling/test_sum_calculator.py
+++ /dev/null
@@ -1,26 +0,0 @@
-# Datei: test_sum_calculator.py
-
-from sum_calculator import calculate_cumulative_sum
-
-def test_sum_for_zero():
-    """Testet den Randfall, wenn die Obergrenze 0 ist."""
-    # Arrange: Testdaten
-    limit = 0
-    # Act: Funktion aufrufen
-    result = calculate_cumulative_sum(limit)
-    # Assert: Überprüfen des Ergebnisses (0 erwartet)
-    assert result == 0
-
-def test_sum_for_five():
-    """Testet den allgemeinen Fall für die Zahl 5 (0+1+2+3+4+5 = 15)."""
-    # Arrange: Testdaten
-    limit = 5
-    # Act: Funktion aufrufen
-    result = calculate_cumulative_sum(limit)
-    # Assert: Überprüfen des Ergebnisses (15 erwartet)
-    assert result == 15
-    
-def test_sum_is_correct_type():
-    """Testet, ob die Funktion einen Integer zurückgibt."""
-    # Arrange, Act, Assert
-    assert isinstance(calculate_cumulative_sum(3), int)
\ No newline at end of file