Island: Remove trailing slashes before registering a URL

Strict slashes seems to not handle a case when URL is defined with a trailing slash, but request is sent without one. Removing trailing slashes before registering a URL will solve the burden of remembering to register URLS without slashes

monkey/monkey_island/cc/app.py

@@ -128,7 +128,7 @@ class FlaskDIWrapper:
             raise ValueError(f"Resource {resource.__name__} has no defined URLs")
 
         self._reserve_urls(resource.urls)
-
+        resource.urls = map(lambda url: url.rstrip("/"), resource.urls)
         dependencies = self._container.resolve_dependencies(resource)
         self._api.add_resource(resource, *resource.urls, resource_class_args=dependencies)
 

monkey/tests/unit_tests/monkey_island/cc/test_app.py

@@ -81,3 +81,11 @@ def test_url_check_slash_stripping__path_separation(resource_manager):
     # Following shouldn't raise and exception
     resource_manager.add_resource(resource3)
     resource_manager.add_resource(resource4)
+
+
+def test_trailing_slash_removal(resource_manager):
+    bogus_endpoint = "/beef/face"
+    resource3 = get_mock_resource("res3", [f"{bogus_endpoint}/"])
+    resource_manager.add_resource(resource3)
+    registered_rules = resource_manager._api.app.url_map._rules
+    assert any([rule.rule == bogus_endpoint for rule in registered_rules])