TextLog - add tests for field event_time_microsec

tests/integration/test_text_log_table/test.py

@@ -22,7 +22,7 @@ def start_cluster():
 
 def test_basic(start_cluster):
     with pytest.raises(QueryRuntimeException):
-        # generates log with "Error" level
+        # generate log with "Error" level
         node.query('SELECT * FROM no_such_table')
 
     node.query('SYSTEM FLUSH LOGS')
@@ -31,3 +31,27 @@ def test_basic(start_cluster):
     assert int(node.query("SELECT count() FROM system.text_log WHERE level = 'Debug'")) == 0
     assert int(node.query("SELECT count() FROM system.text_log WHERE level = 'Information'")) >= 1
     assert int(node.query("SELECT count() FROM system.text_log WHERE level = 'Error'")) >= 1
+
+# compare the event_time and event_time_microseconds and test
+# that they are exactly equal upto their seconds parts.
+def test_field_event_time_microseconds(start_cluster):
+    with pytest.raises(QueryRuntimeException):
+        # generate log with "Error" level
+        node.query('SELECT * FROM no_such_table')
+    node.query('SYSTEM FLUSH LOGS')
+    equals_query = '''WITH (
+                        (
+                            SELECT event_time_microseconds
+                            FROM system.text_log
+                            ORDER BY event_time DESC
+                            LIMIT 1
+                        ) AS time_with_microseconds, 
+                        (
+                            SELECT event_time
+                            FROM system.text_log
+                            ORDER BY event_time DESC
+                            LIMIT 1
+                        ) AS time)
+                    SELECT if(dateDiff('second', toDateTime(time_with_microseconds), toDateTime(time)) = 0, 'ok', 'fail') 
+    '''
+    assert 'ok\n' in node.query(equals_query)