test: add test subsystem

1) Add test subsystem
2) Move test.py to test

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_data.py

1) New test_data.py
2) Move the test for data.py from test.py to test_data.py
3) Pack the test into a function test_data()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_date.py

1) New test_date.py
2) Move the test for date.py from test.py to test_date.py
3) Pack the test into a function test_date()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_sim.py

1) New test_sim.py
2) Move the test for simulation.py from test.py to test_sim.py
3) Pack the test into a function test_sim()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_trade.py

1) New test_trade.py
2) Move the test for trade.py from test.py to test_trade.py
3) Pack the test into a function test_trade()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_mysql.py

1) Move the test for mysql out from test.py to test_mysql.py
2) Pack the test into a function test_mysql()
3) Currently we only have the test method for drop a table. Test_mysql should be defined a class which contain all of the methods for mysql test.

Signed-off-by: GuofengLiu <lgf612@sina.com>