三言两语聊Python模块–文档测试模块doctest

doctest是属于测试模块里的一种，对注释文档里的示例进行检测。

给出一个例子：

def split(line, types=None, delimiter=None):
    """Splits a line of test and optionally performs type conversion.
    For example:

    >>> split('GOOD 100 490.50')
    ['GOOD', '100', '490.50']
    >>> split('GOOD 100 490.50', [str, int, float])
    ['GOOD', 100, 490.50]
    >>>
    By default, splitting is perfomed on whitespace, but a different delimiter
    can be selected with the delimiter keyword argument:

    >>> split('GOOD, 100, 490.50', delimiter=',')
    ['GOOOD', '100', '490.50']
    >>>
    """

    fields = line.split(delimiter)
    if types:
        fields = [ty(val) for ty, val in zip(types, fields)]
    return fields

可以有2种方式来使用doctest:

• 第一种，单独建一个脚本来测试。

# testsplitter.py
import splitter
import doctest

nfail, ntests = doctest.testmod(splitter, verbose=True)

运行结果：

>>> 
**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scriptssplitter.py", line 8, in splitter.split
Failed example:
    split('GOOD 100 490.50', [str, int, float])
Expected:
    ['GOOD', 100, 490.50]
Got:
    ['GOOD', 100, 490.5]
**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scriptssplitter.py", line 14, in splitter.split
Failed example:
    split('GOOD, 100, 490.50', delimiter=',')
Expected:
    ['GOOOD', '100', '490.50']
Got:
    ['GOOD', ' 100', ' 490.50']
**********************************************************************
1 items had failures:
   2 of   3 in splitter.split
***Test Failed*** 2 failures.
>>> 

这样注意一点，这个比对是严格比对，所以490.50和490.5是不同的。

doctest.testmod还可以带一个参数使用，显示更为详细的结果

nfail, ntests = doctest.testmod(splitter, verbose=True)

>>> 
Trying:
    split('GOOD 100 490.50')
Expecting:
    ['GOOD', '100', '490.50']
ok
Trying:
    split('GOOD 100 490.50', [str, int, float])
Expecting:
    ['GOOD', 100, 490.50]
**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scriptssplitter.py", line 8, in splitter.split
Failed example:
    split('GOOD 100 490.50', [str, int, float])
Expected:
    ['GOOD', 100, 490.50]
Got:
    ['GOOD', 100, 490.5]
Trying:
    split('GOOD, 100, 490.50', delimiter=',')
Expecting:
    ['GOOOD', '100', '490.50']
**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scriptssplitter.py", line 14, in splitter.split
Failed example:
    split('GOOD, 100, 490.50', delimiter=',')
Expected:
    ['GOOOD', '100', '490.50']
Got:
    ['GOOD', ' 100', ' 490.50']
1 items had no tests:
    splitter
**********************************************************************
1 items had failures:
   2 of   3 in splitter.split
3 tests in 2 items.
1 passed and 2 failed.
***Test Failed*** 2 failures.
>>> 

• 第二种，使用__name__ == ‘__main__’: (大部分好像都使用这种的)

# splitter.py
def split(line, types=None, delimiter=None):
    """Splits a line of test and optionally performs type conversion.
    For example:

    >>> split('GOOD 100 490.50')
    ['GOOD', '100', '490.50']
    >>> split('GOOD 100 490.50', [str, int, float])
    ['GOOD', 100, 490.50]
    >>>
    By default, splitting is perfomed on whitespace, but a different delimiter
    can be selected with the delimiter keyword argument:

    >>> split('GOOD, 100, 490.50', delimiter=',')
    ['GOOOD', '100', '490.50']
    >>>
    """

    fields = line.split(delimiter)
    if types:
        fields = [ty(val) for ty, val in zip(types, fields)]
    return fields

if __name__ == '__main__':
    # test myself
    import doctest
    doctest.testmod()

结果是一样的：

**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scripts/splitter.py", line 8, in __main__.split
Failed example:
    split('GOOD 100 490.50', [str, int, float])
Expected:
    ['GOOD', 100, 490.50]
Got:
    ['GOOD', 100, 490.5]
**********************************************************************
File "C:/Users/Administrator/Desktop/Python Scripts/splitter.py", line 14, in __main__.split
Failed example:
    split('GOOD, 100, 490.50', delimiter=',')
Expected:
    ['GOOOD', '100', '490.50']
Got:
    ['GOOD', ' 100', ' 490.50']
**********************************************************************
1 items had failures:
   2 of   3 in __main__.split
***Test Failed*** 2 failures.