[TD-1636]<test> remove last 2 bytes of file 'wal0'

tests/pytest/table/alter_wal0.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 tdLog
+from util.cases import tdCases
+from util.sql import tdSql
+from util.dnodes import tdDnodes
+
+
+class TDTestCase:
+    """
+    remove last tow bytes of file 'wal0',then restart taosd and create new tables.
+    """
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor(), logSql)
+
+    def run(self):
+        tdSql.prepare()
+
+        print("==============step1")
+        tdSql.execute("create database if not exists demo;");
+        tdSql.execute("use demo;")
+        tdSql.execute("create table if not exists meters(ts timestamp, f1 int) tags(t1 int);");
+        for i in range(1,11):
+            tdSql.execute("CREATE table if not exists test{num} using meters tags({num});".format(num=i))
+        print("==============insert 10 tables")
+
+        tdSql.query('show tables;')
+        tdSql.checkRows(10)
+
+        print("==============step2")
+        tdDnodes.stopAll()
+        filename = '/var/lib/taos/mnode/wal/wal0'
+
+        with open(filename, 'rb') as f1:
+            temp = f1.read()
+
+        with open(filename, 'wb') as f2:
+            f2.write(temp[:-2])
+
+        tdDnodes.start(1)
+        print("==============remove last tow bytes of file 'wal0' and restart taosd")
+        
+        print("==============step3")
+        tdSql.execute("use demo;")
+        tdSql.query('show tables;')
+        tdSql.checkRows(10)
+        for i in range(11,21):
+            tdSql.execute("CREATE table if not exists test{num} using meters tags({num});".format(num=i))
+
+        tdSql.query('show tables;')
+        tdSql.checkRows(20)
+        print("==============check table numbers and create 10 tables")
+
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())