def test_shepp2d(self):
        assert_equals(shepp2d().dtype, 'float32')
        assert_equals(shepp2d().shape, (1, 512, 512))
        assert_equals(shepp2d(size=(128, 256)).shape, (1, 128, 256))
        assert_equals(shepp2d(size=64).shape, (1, 64, 64))