[ADD] CI for unittests

.github/workflows/on_PR.yml

@@ -0,0 +1,18 @@
+name: tests
+on: [pull_request]
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+      - name: Setup Python
+        uses: actions/setup-python@master
+        with:
+          python-version: 3.7
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest
+          pip install -r requirements.txt
+      - name: Unit tests
+        run: pytest bids_prov