added test section for pip installed version

Author: shimwell

.github/workflows/tests.yml

@@ -3,7 +3,7 @@ name: Tests
 on: [push, pull_request]
 
 jobs:
-  tests:
+  tests-with-conda-install:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -27,3 +27,17 @@ jobs:
         with:
           name: exported-meshes
           path: "*.msh"
+
+  tests-with-pip-install:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+      - name: Install dependencies
+        run: |
+          python -m pip install .
+      - name: Run tests
+        run: python -m pytest -v