Install package itself for tests

Author: takluyver

.github/workflows/test.yml

@@ -32,7 +32,7 @@ jobs:
     - name: Install dependencies
       run: |
         python3 -m pip install --upgrade pip
-        python3 -m pip install pytest
+        python3 -m pip install "." pytest
 
     - name: Test with pytest
       run: |