Use suggested python path

.github/workflows/ci.yml

@@ -36,10 +36,10 @@ jobs:
         run: python -m pip install pyyaml
       
       - name: Test python scripts
-        run: |
-          cd custom
-          python -m unittest
-          cd ..
+        working-directory: custom
+        env:
+          PYTHONPATH: src/
+        run: python -m unittest
 
       - name: Set test tag variable as an output
         id: vars

tests/__init__.py

@@ -1,2 +0,0 @@
-import sys
-sys.path.insert(0, "src")