switched from coverage to pytest-cov

this will report test failures in pipeline

.coveragerc

@@ -0,0 +1,20 @@
+[run]
+# ignore GUI code atm.
+omit =
+    NanoVNASaver/Analysis.py
+    NanoVNASaver/Calibration.py
+    NanoVNASaver/Chart.py
+    NanoVNASaver/Hardware.py
+    NanoVNASaver/Inputs.py
+    NanoVNASaver/Marker/Settings.py
+    NanoVNASaver/Marker/Values.py
+    NanoVNASaver/Marker/Widget.py
+    NanoVNASaver/Marker/__init__.py
+    NanoVNASaver/NanoVNASaver.py
+    NanoVNASaver/SweepWorker.py
+    NanoVNASaver/__init__.py
+    NanoVNASaver/__main__.py
+    NanoVNASaver/about.py
+[report]
+fail_under = 90.0
+show_missing = True

.github/workflows/pythonapp.yml

@@ -21,8 +21,7 @@ jobs:
       run: |
         pip install pylint
         pylint --exit-zero NanoVNASaver
-    - name: Unittests
+    - name: Unittests / Coverage
       run: |
-        pip install coverage
-        coverage run ./test_master.py
-        coverage report --fail-under=90 -m --skip-covered
+        pip install pytest-cov
+        pytest  --cov=NanoVNASaver