python - 单元测试 Tornado 应用程序: How to improve the display of error messages

Question

我正在使用unittest来测试一个 Tornado 应用程序，该应用程序有多个处理程序，其中一个处理程序引发了异常。如果我使用 python test.py 运行以下测试代码:

# test.py

import unittest
import tornado.web
import tornado.testing

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write('Hello World') # handler works correctly

class HandlerWithError(tornado.web.RequestHandler):
    def get(self):
        raise Exception('Boom') # handler raises an exception
        self.write('Hello World')

def make_app():
    return tornado.web.Application([
        (r'/main/', MainHandler),
        (r'/error/', HandlerWithError),
    ])

class TornadoTestCase(tornado.testing.AsyncHTTPTestCase):

    def get_app(self):
        return make_app()

    def test_main_handler(self):
        response = self.fetch('/main/')
        self.assertEqual(response.code, 200) # test should pass

    def test_handler_with_error(self):
        response = self.fetch('/error/')
        self.assertEqual(response.code, 200) # test should fail with error

if __name__ == '__main__':
    unittest.main()

测试输出如下:

ERROR:tornado.application:Uncaught exception GET /error/ (127.0.0.1)                                                                                                                   
HTTPServerRequest(protocol='http', host='localhost:36590', method='GET', uri='/error/', version='HTTP/1.1', remote_ip='127.0.0.1', headers={'Connection': 'close', 'Host': 'localhost:3
6590', 'Accept-Encoding': 'gzip'})                                                                                                                                                     
Traceback (most recent call last):                                                                                                                                                     
  File "/usr/local/lib/python2.7/dist-packages/tornado/web.py", line 1332, in _execute                                                                                                 
    result = method(*self.path_args, **self.path_kwargs)                                                                                                                               
  File "test.py", line 13, in get                                                                                                                                                      
    raise Exception('Boom') # handler raises an exception                                                                                                                              
Exception: Boom                                                                                                                                                                        
ERROR:tornado.access:500 GET /error/ (127.0.0.1) 19.16ms                                                                                                                               
F.                                                                                                                                                                                     
======================================================================                                                                                                                 
FAIL: test_handler_with_error (__main__.TornadoTestCase)                                                                                                                               
----------------------------------------------------------------------                                                                                                                 
Traceback (most recent call last):                                                                                                                                                     
  File "/usr/local/lib/python2.7/dist-packages/tornado/testing.py", line 118, in __call__                                                                                              
    result = self.orig_method(*args, **kwargs)                                                                                                                                         
  File "test.py", line 33, in test_handler_with_error                                                                                                                                  
    self.assertEqual(response.code, 200) # test should fail with error                                                                                                                 
AssertionError: 500 != 200                                                                                                                                                             

----------------------------------------------------------------------                                                                                                                 
Ran 2 tests in 0.034s                                                                                                                                                                  

FAILED (failures=1)       

但是，我希望 unittest 在第二次测试中报告错误，而不是失败的断言。此外，“Boom”异常的回溯出现在单元测试测试报告之前，并且不包含对失败的测试函数的引用，这使得很难找到异常的来源。

有什么建议如何处理这种情况吗？

提前致谢!

编辑

令我意想不到的是，test_handler_with_error 实际上到达了 assertEqual 断言，而不是抛出错误。例如，以下代码不执行 self.assertEqual 语句，因此在测试输出中报告 ERROR 而不是 FAIL:

# simple_test.py
import unittest

def foo():
    raise Exception('Boom')
    return 'bar'

class SimpleTestCase(unittest.TestCase):
    def test_failing_function(self):
        result = foo()
        self.assertEqual(result, 'bar')

if __name__ == '__main__':
    unittest.main()

Answer 1

您可以禁用日志记录，这样只会显示测试报告:

logging.disable(logging.CRITICAL)

例如，您可以将其放入

• 创建了 TestCase 子类
• 测试运行者

更多信息How can I disable logging while running unit tests in Python Django?

请记住，CI/CD 系统实际上使用标准化报告，例如junit，然后以更易读/更优雅的方式呈现它 - 更多信息:

• Python script to generate JUnit report from another testing result
• How to output coverage XML with nosetests?