Sample operator test codeΒΆ

Many examples from the documentation end by calling function expect to check a runtime returns the expected outputs for the given example. Here is one implementation based on onnxruntime.

from typing import Any, Sequence
import numpy as np
import onnx
import onnxruntime

def expect(
    node: onnx.NodeProto,
    inputs: Sequence[np.ndarray],
    outputs: Sequence[np.ndarray],
    name: str,
    **kwargs: Any,
) -> None:
    # Builds the model
    present_inputs = [x for x in node.input if (x != "")]
    present_outputs = [x for x in node.output if (x != "")]
    input_type_protos = [None] * len(inputs)
    if "input_type_protos" in kwargs:
        input_type_protos = kwargs["input_type_protos"]
        del kwargs["input_type_protos"]
    output_type_protos = [None] * len(outputs)
    if "output_type_protos" in kwargs:
        output_type_protos = kwargs["output_type_protos"]
        del kwargs["output_type_protos"]
    inputs_vi = [
        _extract_value_info(arr, arr_name, input_type)
        for arr, arr_name, input_type in zip(inputs, present_inputs, input_type_protos)
    outputs_vi = [
        _extract_value_info(arr, arr_name, output_type)
        for arr, arr_name, output_type in zip(
            outputs, present_outputs, output_type_protos
    graph = onnx.helper.make_graph(
        nodes=[node], name=name, inputs=inputs_vi, outputs=outputs_vi
    kwargs["producer_name"] = "backend-test"

    if "opset_imports" not in kwargs:
        # To make sure the model will be produced with the same opset_version after opset changes
        # By default, it uses since_version as opset_version for produced models
        produce_opset_version = onnx.defs.get_schema(
            node.op_type, domain=node.domain
        kwargs["opset_imports"] = [
            onnx.helper.make_operatorsetid(node.domain, produce_opset_version)

    model = onnx.helper.make_model_gen_version(graph, **kwargs)

    # Checking the produces are the expected ones.
    sess = onnxruntime.InferenceSession(model.SerializeToString(),
    feeds = {name: value for name, value in zip(node.input, inputs)}
    results =, feeds)
    for expected, output in zip(outputs, results):
        assert_allclose(expected, output)