def METHOD_NAME(self):
    self.runModule("g.region", res3=10, n=100, s=0, w=0, e=120, b=0, t=50)
    self.assertModuleFail(
        "r3.gradient",
        input="test_map_1_ref",
        output=["test_grad_x", "test_grad_y"],
        overwrite=True,
    )
    self.assertModule(
        "r3.gradient",
        input="test_map_1_ref",
        output=["test_grad_x", "test_grad_y", "test_grad_z"],
        overwrite=True,
    )