Add test

tests/integration/test_log_levels_update/configs/log.xml

@@ -0,0 +1,6 @@
+<yandex>
+    <logger>
+        <level>trace</level>
+        <log>/var/log/clickhouse-server/clickhouse-server.log</log>
+    </logger>
+</yandex>

tests/integration/test_log_levels_update/test.py

@@ -0,0 +1,50 @@
+import pytest
+import re
+
+from helpers.cluster import ClickHouseCluster
+
+cluster = ClickHouseCluster(__file__, name="log_quries_probability")
+node = cluster.add_instance('node', with_zookeeper=False)
+
+config = '''<yandex>
+    <logger>
+        <level>information</level>
+        <log>/var/log/clickhouse-server/clickhouse-server.log</log>
+    </logger>
+</yandex>'''
+
+
+@pytest.fixture(scope="module")
+def start_cluster():
+    try:
+        cluster.start()
+        yield cluster
+
+    finally:
+        cluster.shutdown()
+
+
+def get_log(node):
+    return node.exec_in_container(["bash", "-c", "cat /var/log/clickhouse-server/clickhouse-server.log"])
+
+def test_log_levels_update(start_cluster):
+    # Make sure that there are enough log messages for the test
+    for i in range(5):
+        node.query("SELECT 1")
+
+    log = get_log(node)
+    assert re.search("(<Trace>|<Debug>)", log)
+
+    node.replace_config("/etc/clickhouse-server/config.d/log.xml", config)
+    node.query("SYSTEM RELOAD CONFIG;")
+    node.exec_in_container(["bash", "-c", "> /var/log/clickhouse-server/clickhouse-server.log"])
+    
+    for i in range(5):
+        node.query("SELECT 1")
+
+    log = get_log(node)
+    assert len(log) > 0
+    assert not re.search("(<Trace>|<Debug>)", log)
+    
+
+