test: add basic unit tests to be sure we can create Robyn and SubRout…

…er with empty lists of routes. This will confirm the imports haven't changed from the docs

unit_tests/test_robyn_app.py

@@ -0,0 +1,16 @@
+from robyn.router import Router
+from robyn import Robyn, SubRouter
+
+
+def test_app_creation():
+    app = Robyn(__file__)
+    router = app.router
+    assert isinstance(router, Router)
+    assert len(router.routes) == 0
+
+
+def test_subrouter_creation():
+    sub = SubRouter(__name__, prefix="/frontend")
+    router = sub.router
+    assert isinstance(router, Router)
+    assert len(router.routes) == 0