def test_conv_bias_fusion(self, compute_unit, backend):
        """
        Test conv bias fusion when const input.


        Input graph:
                                        Const
                                          |
                                          V
        input -----> convolution -----> add/sub  ---> out

        Output graph:
        input -----> convolution -----> out
        """
        weight = np.array([2.5], dtype=np.float32).reshape([1, 1, 1, 1])

        def build(x):
            x = mb.conv(x=x, weight=weight)
            bias = mb.const(val=[10.0])
            return mb.add(x=x, y=bias)

        input = np.array([1, 2, 3, 4], dtype=np.float32).reshape((1, 1, 2, 2))
        output = np.array([12.5, 15.0, 17.5, 20.0], dtype=np.float32).reshape((1, 1, 2, 2))
        expected_output_types = output.shape + (types.fp32,)
        expected_outputs = [output]
        input_placeholders = {"x": mb.placeholder(shape=input.shape)}
        input_values = {"x": input}

        run_compare_builder(
            build,
            input_placeholders,
            input_values,
            expected_output_types,
            expected_outputs,
            compute_unit=compute_unit,
            backend=backend,
        )

        Test conv bias fusion when const input.


        Input graph:
                                        Const
                                          |
                                          V
        input -----> convolution -----> add/sub  ---> out

        Output graph:
        input -----> convolution -----> out
        
coremltools/converters/mil/mil/ops/tests/iOS14/test_conv.py