Update test action to make sure import works before installing dev de…

…pendencies

.github/workflows/tests.yaml

@@ -33,14 +33,14 @@ jobs:
         uses: actions/setup-python@v2
         with:
           python-version: ${{ matrix.python-version }}
-      - name: Install dependencies
+      - name: Install without dev dependencies
         run: |
           pip install --upgrade pip setuptools wheel
-          pip install --only-binary=numpy,scipy -r requirements-dev.txt
-      - name: Install package
-        run: |
+          pip install --only-binary=numpy,scipy -r requirements.txt
           pip install .
+      - name: Make sure import works
+        run: python -c "import becquerel;"
+      - name: Install dev dependencies
+        run: pip install -r requirements-dev.txt
       - name: Test with pytest
-        run: |
-          python -c 'import becquerel;'
-          pytest
+        run: pytest