actions: Add action to run all tests

And: Add to .gitignore

.github/workflows/run-tests.yml

@@ -0,0 +1,19 @@
+name: Run all tests
+on: [push, pull_request]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+        architecture: x64
+    - uses: actions/cache@v1
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
+    - run: pip install -r requirements_test.txt
+    - run: pytest tests

.gitignore

@@ -1,4 +1,6 @@
 .ve
 *.swp
 *~
-_build
+_build
+.pyest*
+__pycache__