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Python 单元测试

时间：2018/1/6 14:36:55
参考：

  1. Testing Your Code
  2. Unit testing framework

unittest#

核心类及方法#

  • TestCase 测试用例要实现的父类

  • TestSuite TestCase和TestSuite的组合

    例子：

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    import unittest

from tests.test_demo import TestDemo

if __name__ == '__main__':

    suite = unittest.TestSuite()
    suite.addTests(unittest.TestLoader().loadTestsFromTestCase(TestDemo))

    try:
        with open("test.txt", mode="w", encoding="utf-8") as t:
            runner = unittest.TextTestRunner(stream=t, verbosity=2)
            runner.run(suite)
    except FileNotFoundError as e:
        print("测试出错", str(e))
    • TestLoader 加载测试用例
    • TestResult 测试用例运行结果
    • TextTestResult 运行测试用例

    • main：启动入口

      if name == 'main': unittest.main(verbosity=2) * load_tests：自定义加载测试方法的方法

测试命令#

  • 查看帮助文档

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    python -m unittest -h

  • 运行某个测试某个文件

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    python -m unittest tests/test.py

  • 不指定参数，会启动自动发现机制

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    python -m unittest  
python -m unittest discover

  • 测试指定模块，路径分隔符替换成 ., python文件去掉 .py 后缀。 

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    python -m unittest tests.test
    • 指定参数：

    • unittest 支持的参数

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      -b, --buffer
The standard output and standard error streams are buffered during the test run. Output during a passing test is discarded. Output is echoed normally on test fail or error and is added to the failure messages.

-c, --catch
Control-C during the test run waits for the current test to end and then reports all the results so far. A second Control-C raises the normal KeyboardInterrupt exception.

See Signal Handling for the functions that provide this functionality.

-f, --failfast
Stop the test run on the first error or failure.

--locals
Show local variables in tracebacks.

    • discover 发现机制支持的参数：

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      -v, --verbose
Verbose output

-s, --start-directory directory
Directory to start discovery (. default)

-p, --pattern pattern
Pattern to match test files (test*.py default)

-t, --top-level-directory directory
Top level directory of project (defaults to start directory)
usecase：

python -m unittest discover -s project_directory -p "*_test.py"
python -m unittest discover project_directory "*_test.py"

测试方法#

  • 资源初始化和资源回收，每个测试方法运行和结束的时候都会调用

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    def setUp(self):
    self.widget = Widget('The widget')

def tearDown(self):
    self.widget.dispose()

    • 跳过测试

    • 添加在方法上

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      @unittest.skip("demonstrating skipping")
@unittest.skipIf(mylib.__version__ < (1, 3), "not supported in this library version")
@unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
* 添加在class 上

@unittest.skip("showing class skipping")
* 写代码跳过

def test_skip_in_code(self):
    self.skipTest("测试代码内跳过测试")
      • 预期的异常

      @unittest.expectedFailure def test_fail(self): self.assertEqual(1, 0, "broken") * 子测试，子测试里面遇到错误，上级测试不会结束，会继续进行测试

      def test_even(self): """ 3.6版本没有效果 """ for i in range(0, 4): with self.subTest(i=i): self.assertEqual(i % 2, 0)