diff --git a/.drone.yml b/.drone.yml
index b9efa2a..5bbd088 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -11,7 +11,7 @@ platform:
 steps:
   - name: Run unit test
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - python3 tests/main.py
 
@@ -28,7 +28,7 @@ platform:
 steps:
   - name: Run unit test
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - python3 tests/main.py
 
@@ -45,7 +45,7 @@ platform:
 steps:
   - name: Run unit test
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - python3 tests/main.py
 
@@ -62,7 +62,7 @@ platform:
 steps:
   - name: Run unit test
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - tox
 
@@ -75,7 +75,7 @@ steps:
   - name: Run unit test
     image: python:3.6
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - pip install python-dateutil
       - tests/main.py
@@ -89,7 +89,7 @@ steps:
   - name: Run unit test
     image: python:latest
     environment:
-      PYTHONPATH: .
+      PYTHONPATH: src
     commands:
       - pip install python-dateutil
       - python --version