[Test] add test for subgraph execution

tests/core/test_basic_onnx_exec.py

@@ -49,19 +49,33 @@ def test_mnist_onnx_download_extract_run():
     raw_o = get_data("finn", "data/onnx/mnist-conv/test_data_set_0/output_0.pb")
     input_tensor = onnx.load_tensor_from_string(raw_i)
     output_tensor = onnx.load_tensor_from_string(raw_o)
-    # run using FINN-based execution
+    # run using FINN-based execution (full graph)
     input_dict = {"Input3": np_helper.to_array(input_tensor)}
-    output_dict = oxe.execute_onnx(model, input_dict)
+    output_dict = oxe.execute_onnx(model, input_dict, return_full_exec_context=True)
     assert np.isclose(
         np_helper.to_array(output_tensor), output_dict["Plus214_Output_0"], atol=1e-3
     ).all()
+    # test subgraph execution
+    start_node = model.graph.node[1]
+    end_node = model.graph.node[3]
+    subgraph_i_dict = {start_node.input[0]: output_dict[start_node.input[0]]}
+    subgraph_o_dict = oxe.execute_onnx(
+        model,
+        subgraph_i_dict,
+        return_full_exec_context=True,
+        start_node=start_node,
+        end_node=end_node,
+    )
+    assert np.isclose(
+        subgraph_o_dict[end_node.output[0]], output_dict[end_node.output[0]], atol=1e-3
+    ).all()
 
 
 def test_onnx_exec_internal_rounding():
     inp0 = onnx.helper.make_tensor_value_info("inp0", onnx.TensorProto.FLOAT, [2, 2])
     inp1 = onnx.helper.make_tensor_value_info("inp1", onnx.TensorProto.FLOAT, [1])
     outp = onnx.helper.make_tensor_value_info("outp", onnx.TensorProto.FLOAT, [2, 2])
-    mul_node = onnx.helper.make_node("Mul", inputs=["inp0", "inp1"], outputs=["outp"],)
+    mul_node = onnx.helper.make_node("Mul", inputs=["inp0", "inp1"], outputs=["outp"])
     graph = onnx.helper.make_graph(
         nodes=[mul_node], name="mul_graph", inputs=[inp0, inp1], outputs=[outp]
     )