add coverage to prototype tests CI (#6630)

* add coverage to prototype tests CI

* line continuation

.github/workflows/prototype-tests.yml

@@ -37,16 +37,31 @@ jobs:
         run: pip install --progress-bar=off scipy pycocotools h5py iopath
 
       - name: Install test requirements
-        run: pip install --progress-bar=off pytest pytest-mock
+        run: pip install --progress-bar=off pytest pytest-mock pytest-cov
 
       - name: Run prototype datasets tests
         shell: bash
-        run: pytest --durations=20 test/test_prototype_datasets*.py
+        run: |
+          pytest \
+            --durations=20 \
+            --cov=torchvision/prototype/datasets \
+            --cov-report=term-missing \
+            test/test_prototype_datasets*.py
 
       - name: Run prototype transforms tests
         shell: bash
-        run: pytest --durations=20 test/test_prototype_transforms*.py
+        run: |
+          pytest \
+            --durations=20 \
+            --cov=torchvision/prototype/transforms \
+            --cov-report=term-missing \
+            test/test_prototype_transforms*.py
 
       - name: Run prototype models tests
         shell: bash
-        run: pytest --durations=20 test/test_prototype_models*.py
+        run: |
+          pytest \
+            --durations=20 \
+            --cov=torchvision/prototype/models \
+            --cov-report=term-missing \
+            test/test_prototype_models*.py