chore: revert tests-on-pr.yml back to original

Author: cadenmyers13

.github/workflows/tests-on-pr.yml

@@ -1,15 +1,47 @@
 name: Tests on PR
 
 on:
+  push:
+    branches:
+      - main
+      - cookie
   pull_request:
   workflow_dispatch:
 
 jobs:
-  tests-on-pr:
-    uses: scikit-package/release-scripts/.github/workflows/_tests-on-pr.yml@v0
-    with:
-      project: diffpy.srreal
-      c_extension: true
-      headless: false
-    secrets:
-      CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+  validate:
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-13, macos-14]
+        python-version: [3.11, 3.12, 3.13]
+
+    steps:
+      - name: Check out diffpy.srreal
+        uses: actions/checkout@v4
+
+      - name: Initialize miniconda
+        uses: conda-incubator/setup-miniconda@v3
+        with:
+          activate-environment: test
+          auto-update-conda: true
+          environment-file: environment.yml
+          auto-activate-base: false
+          python-version: ${{ matrix.python-version }}
+
+      - name: Conda config
+        run: >-
+          conda config --set always_yes yes
+          --set changeps1 no
+      - name: Install diffpy.srreal and requirements
+        run: |
+          conda install --file requirements/conda.txt
+          conda install --file requirements/test.txt
+          python -m pip install . --no-deps
+      - name: Validate diffpy.pdfgui
+        run: pytest tests