class TestAbs(OpTest):
    def setUp(self):
        self.op_type = "abs"
        x = np.random.uniform(-1, 1, [4, 4]).astype("float32")
        # Because we set delta = 0.005 in caculating numeric gradient,
        # if x is too small, such as 0.002, x_neg will be -0.003
        # x_pos will be 0.007, so the numeric gradient is unaccurate.
        # we should avoid this
        x[np.abs(x) < 0.005] = 0.02
        self.inputs = {'X': x}
        self.outputs = {'Y': np.abs(self.inputs['X'])}

    def test_check_output(self):
        self.check_output()

    def test_check_grad(self):
        self.check_grad(['X'], 'Y', max_relative_error=0.007)