'Tests that appropriate exceptions are raised.'

def test_exceptions(self):

    fs = self.cluster.fs
    test_file = (self.prefix + '/for_exception_test.txt')
    f = fs.open(test_file, 'w')
    f.write('foo')
    f.close()
    fs.chmod(test_file, 256)
    fs.setuser('notsuperuser')
    f = fs.open(test_file)
    assert_raises(WebHdfsException, f.read)
