Add a local pytest plugin to allow overwriting Loki log level

conftest.py

@@ -0,0 +1,37 @@
+# (C) Copyright 2018- ECMWF.
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+
+"""
+Local pytest plugin to add bespoke pytest extensions for Loki
+
+See the pytest documentation for more details:
+https://docs.pytest.org/en/stable/how-to/writing_plugins.html#local-conftest-plugins
+"""
+
+from loki.config import config as loki_config
+
+
+def pytest_addoption(parser, pluginmanager):  # pylint: disable=unused-argument
+    """
+    Add options to the pytest CLI
+
+    Additional options can be specified via ``parser.addoption`` using the same signature as
+    :any:`argparse.ArgumentParser.add_argument`.
+
+    For Loki, we add ``--loki-log-level`` to overwrite the log level in :any:`loki.logging`.
+    """
+    parser.addoption('--loki-log-level', dest='LOKI_LOG_LEVEL', default='INFO',
+                     help='Change the Loki log level (ERROR, WARNING, INFO, PERF, DETAIL, DEBUG)')
+
+
+def pytest_configure(config):
+    """
+    Apply configuration changes
+
+    This function is invoked after all command line options have been processed
+    """
+    loki_config['log-level'] = config.option.LOKI_LOG_LEVEL