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):
@@ -79,6 +82,9 @@ def benchmark(request):
 def pytest_terminal_summary(terminalreporter):
     tr = terminalreporter
     results = tr.config._benchresults
+    if not results:
+        return
+
     tr.section("benchmark results")
     float_names = 'median min max'.split()
     width = max(map(len, float_names))

online-tests/pytest.ini

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