Add placeholder test

tests/test_nothing.py

@@ -0,0 +1,2 @@
+def test_nothing():
+    pass

tox.ini

@@ -7,7 +7,7 @@ description = Run the unit tests (pytest)
 deps =
     pytest
     pytest-cov
-commands = 
+commands =
     pytest --cov={envsitepackagesdir}/keyosk --cov-config {env:HOME}/.coveragerc tests/ --cov-report term-missing
 
 [testenv:lint]
@@ -22,14 +22,14 @@ commands =
 
 [testenv:typing]
 description = Check type annotations with mypy
-deps = 
+deps =
     mypy
-commands = 
+commands =
     mypy keyosk --ignore-missing-imports --no-strict-optional
 
 [testenv:security]
 description = Check security vulnerabilities (bandit)
-deps = 
+deps =
     bandit
 commands =
     bandit --recursive keyosk