[TD-2036] add test case for arithmetic

tests/pytest/functions/function_arithmetic.py

+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+import sys
+import taos
+from util.log import *
+from util.cases import *
+from util.sql import *
+import numpy as np
+
+
+class TDTestCase:
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor())
+
+        self.rowNum = 10
+        self.ts = 1537146000000
+        
+    def run(self):
+        tdSql.prepare()
+
+        tdSql.execute('''create table test(ts timestamp, col1 int, col2 int) tags(loc nchar(20))''')
+        tdSql.execute("create table test1 using test tags('beijing')")
+        tdSql.execute("create table test2 using test tags('shanghai')")
+        for i in range(self.rowNum):
+            tdSql.execute("insert into test1 values(%d, %d, %d)" % (self.ts + i, i + 1, i + 1))
+            tdSql.execute("insert into test2 values(%d, %d, %d)" % (self.ts + i, i + 1, i + 1))
+
+        # arithmetic verifacation
+        tdSql.query("select 0.1 + 0.1 from test")
+        tdSql.checkRows(self.rowNum * 2)
+        for i in range(self.rowNum * 2):
+            tdSql.checkData(0, 0, 0.20000000)
+        
+        tdSql.query("select 4 * avg(col1) from test")
+        tdSql.checkRows(1)        
+        tdSql.checkData(0, 0, 22)
+
+        tdSql.query("select 4 * sum(col1) from test")
+        tdSql.checkRows(1)        
+        tdSql.checkData(0, 0, 440)
+
+        tdSql.query("select 4 * avg(col1) * sum(col2) from test")
+        tdSql.checkRows(1)        
+        tdSql.checkData(0, 0, 2420)
+
+        tdSql.query("select 4 * avg(col1) * sum(col2) from test group by loc")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, 1210)
+        tdSql.checkData(1, 0, 1210)
+
+        tdSql.error("select avg(col1 * 2)from test group by loc")
+                
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())