add marker dynamically to allow "pytest" to execute nicely at repo root without warnings

online-tests/conftest.py

@@ -18,6 +18,9 @@ def pytest_addoption(parser):
 
 def pytest_configure(config):
     config._benchresults = {}
+    config.addinivalue_line(
+        "markers", "slow: mark test to require --slow option to run"
+    )
 
 
 def pytest_runtest_setup(item):

online-tests/pytest.ini

@@ -1,3 +1,2 @@
 [pytest]
 addopts = -vrsx --strict-markers
-markers = slow: mark test as slow (requires --slow option to run)