Merge pull request #6524 from taosdata/xiaoping/add_test_case

[TD-4733]<test>: add test case for derivative function

tests/pytest/functions/function_derivative.py

@@ -130,6 +130,13 @@ class TDTestCase:
         tdSql.prepare()        
         self.insertAndCheckData()
 
+        tdSql.execute("create table st(ts timestamp, c1 int, c2 int) tags(id int)")
+        tdSql.execute("insert into dev1(ts, c1) using st tags(1) values(now, 1)")
+
+        tdSql.error("select derivative(c1, 10s, 0) from (select c1 from st)")
+        tdSql.query("select diff(c1) from (select derivative(c1, 1s, 0) c1 from dev1)")
+        tdSql.checkRows(0)
+              
     def stop(self):
         tdSql.close()
         tdLog.success("%s successfully executed" % __file__)