update tests for refl1d to use pip

.github/workflows/validate_refl1d.yml

@@ -0,0 +1,35 @@
+name: ORSO Val. Refl1D
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+  schedule:
+    - cron:  '0 0 * * 1'
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+
+jobs:
+  validate_ref1d:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.9'
+
+      - name: Install Python packages
+        run: |
+          python -m pip install numpy scipy cython pytest
+          # install refl1d from source (because the last release requires
+          # wxpython which requires a lot of time to build, the git repo doesn't
+          # at time of writing)
+          python -m pip install refl1d --pre
+
+      - name: Validate
+        run: |
+          # run validation via pytest (for Python packages)
+          pytest validation/scripts/test_refl1d.py