runner.py 文件源码

def importorskip(modname, minversion=None):
    """ return imported module if it has at least "minversion" as its
    __version__ attribute.  If no minversion is specified the a skip
    is only triggered if the module can not be imported.
    """
    __tracebackhide__ = True
    compile(modname, '', 'eval') # to catch syntaxerrors
    should_skip = False
    try:
        __import__(modname)
    except ImportError:
        # Do not raise chained exception here(#1485)
        should_skip = True
    if should_skip:
        raise Skipped("could not import %r" %(modname,), allow_module_level=True)
    mod = sys.modules[modname]
    if minversion is None:
        return mod
    verattr = getattr(mod, '__version__', None)
    if minversion is not None:
        try:
            from pkg_resources import parse_version as pv
        except ImportError:
            raise Skipped("we have a required version for %r but can not import "
                          "pkg_resources to parse version strings." % (modname,),
                          allow_module_level=True)
        if verattr is None or pv(verattr) < pv(minversion):
            raise Skipped("module %r has __version__ %r, required is: %r" %(
                          modname, verattr, minversion), allow_module_level=True)
    return mod