python __import__(module)

如果要 import 的模块是字符串(比如利用参数进行传递)，可以事业 builtin 的 __import() 函数，例如：

def __init__(self, module='__main__', defaultTest=None,
             argv=None, testRunner=None, testLoader=defaultTestLoader):
    if type(module) == type(''):
        self.module = __import__(module)
        for part in module.split('.')[1:]:
            self.module = getattr(self.module, part)
        else:
            self.module = module

又如：

mod = __import__('random')

当然也可以使用

exec "import %s as mod" % module

来解决。

可以看看 unittest 对它的使用，得到一个更清楚的认识：

class TestLoader:
    ...
    def loadTestsFromModule(self, module):
        """Return a suite of all tests cases contained in the given module"""
        tests = []
        for name in dir(module):
            obj = getattr(module, name)
            if (isinstance(obj, (type, types.ClassType)) and
                issubclass(obj, TestCase)):
                tests.append(self.loadTestsFromTestCase(obj))
        return self.suiteClass(tests)

......

class TestProgram:
    def __init__(self, module='__main__', defaultTest=None,
                 argv=None, testRunner=None, testLoader=defaultTestLoader):
        if type(module) == type(''):
            self.module = __import__(module)
            for part in module.split('.')[1:]:
                self.module = getattr(self.module, part)
        else:
            self.module = module
    ...
    def parseArgs(self, argv):
        import getopt
        try:
            options, args = getopt.getopt(argv[1:], 'hHvq',
                                          ['help','verbose','quiet'])
            for opt, value in options:
                if opt in ('-h','-H','--help'):
                    self.usageExit()
                if opt in ('-q','--quiet'):
                    self.verbosity = 0
                if opt in ('-v','--verbose'):
                    self.verbosity = 2
            if len(args) == 0 and self.defaultTest is None:
                self.test = self.testLoader.loadTestsFromModule(self.module)
                return
            if len(args) > 0:
                self.testNames = args
            else:
                self.testNames = (self.defaultTest,)
            self.createTests()
        except getopt.error, msg:
            self.usageExit(msg)