ddt运行测试方法时报错AttributeError: type object 'TestHttpRq' has no attribute 'test_http_rq_login'

 import unittest
 import ddt  #装饰器
 from ddt import ddt,data,unpack #导入ddt中的各个模块
 from homework.unittest_http_request_20190321.Method_http_request import *

 @ddt  #装饰测试类
 class TestHttpRq(unittest.TestCase): #测试类-get请求

     @data({"mobilephone":"","pwd":""},
           {"mobilephone":"","pwd":""},
           {"mobilephone": "", "pwd": ""},
           {"mobilephone":"","pwd":""}) #装饰方法，遍历data中的元素
     def test_http_rq_login(self,login_data):#测试用例必须以test开头，不然报错
       exp = ["用户名或密码错误","登录成功","手机号不能为空","密码不能为空"]
       res = HttpRequest("get",login_data).http_request().json()['msg']
       self.assertIn(res,exp)#断言,判断实际值与预期值是否一致

 D:\Python34\python.exe "D:\Program Files\JetBrains\PyCharm Community Edition 2017.2.3\helpers\pycharm\_jb_unittest_runner.py" --target unittest_http_rq.TestHttpRq.test_http_rq_login
 Testing started at 13:10 ...
 Launching unittests with arguments python -m unittest unittest_http_rq.TestHttpRq.test_http_rq_login in D:\python15期\homework\ddt_20190323

 Traceback (most recent call last):
   File "D:\Program Files\JetBrains\PyCharm Community Edition 2017.2.3\helpers\pycharm\_jb_unittest_runner.py", line 35, in <module>
     main(argv=args, module=None, testRunner=unittestpy.TeamcityTestRunner, buffer=not JB_DISABLE_BUFFERING)
   File "D:\Python34\lib\unittest\main.py", line 92, in __init__
     self.parseArgs(argv)
   File "D:\Python34\lib\unittest\main.py", line 139, in parseArgs
     self.createTests()
   File "D:\Python34\lib\unittest\main.py", line 146, in createTests
     self.module)
   File "D:\Python34\lib\unittest\loader.py", line 157, in loadTestsFromNames
     suites = [self.loadTestsFromName(name, module) for name in names]
   File "D:\Python34\lib\unittest\loader.py", line 157, in <listcomp>
     suites = [self.loadTestsFromName(name, module) for name in names]
   File "D:\Python34\lib\unittest\loader.py", line 125, in loadTestsFromName
     parent, obj = obj, getattr(obj, part)
 AttributeError: type object 'TestHttpRq' has no attribute 'test_http_rq_login'

 Process finished with exit code 1
 Empty test suite.

_{运行程序时将鼠标定位在类或者程序外运行解决，ddt只能运行整体，不能运行局部即单个测试方法}