Add new apptest for streamlit

tests/test_apptest.py

@@ -0,0 +1,7 @@
+# file: D:/Projects/Battlewords/tests/test_apptest.py
+from streamlit.testing.v1 import AppTest
+
+def test_app_runs():
+    at = AppTest.from_file("app.py")
+    at.run()
+    assert not at.exception