import py, os.path

def setup_module(mod):
    mod.tmpdir = py.test.ensuretemp(__name__)

class TestOS:
    def setup_method(self, method):
        self.tmpdir = tmpdir.mkdir(method.__name__)
        print "chdir() to ", self.tmpdir
        self.oldcwd = self.tmpdir.chdir()
    def teardown_method(self, method):
        self.oldcwd.chdir()

    def test_relative(self):
        p = "a/b" 
        expected = os.path.join(str(self.tmpdir), p)
        assert os.path.abspath(p) == expected  + "xxx"