Can now load and run a network

- The library is now capable of loading the test session and running
   it successfully.

 - Updated the example application, which is really the same as the test
   and should probably be deleted.

 - TODO: The input names actually *do* need to match the names when the
   network was created. The hardcoded names in onnxruntime_wrapper.c
   will *not* do!

onnx_example_application/onnx_example_application.go

@@ -3,12 +3,39 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"github.com/yalue/onnxruntime"
 	"os"
 	"runtime"
 )
 
+// This type is read from JSON and used to determine the inputs and expected
+// outputs for an ONNX network.
+type testInputsInfo struct {
+	InputShape      []int64   `json:"input_shape"`
+	FlattenedInput  []float32 `json:"flattened_input"`
+	OutputShape     []int64   `json:"output_shape"`
+	FlattenedOutput []float32 `json:"flattened_output"`
+}
+
+// Loads JSON that contains the shapes and data used by the test ONNX network.
+// Requires the path to the JSON file.
+func loadInputsJSON(path string) (*testInputsInfo, error) {
+	f, e := os.Open(path)
+	if e != nil {
+		return nil, fmt.Errorf("Error opening %s: %w", path, e)
+	}
+	defer f.Close()
+	d := json.NewDecoder(f)
+	var toReturn testInputsInfo
+	e = d.Decode(&toReturn)
+	if e != nil {
+		return nil, fmt.Errorf("Error decoding %s: %w", path, e)
+	}
+	return &toReturn, nil
+}
+
 func run() int {
 	if runtime.GOOS == "windows" {
 		onnxruntime.SetSharedLibraryPath("../test_data/onnxruntime.dll")
@@ -26,6 +53,52 @@ func run() int {
 	}
 	fmt.Printf("The onnxruntime environment initialized OK.\n")
 
+	// Load the JSON with the test input and output data.
+	testInputs, e := loadInputsJSON(
+		"../test_data/example_network_results.json")
+	if e != nil {
+		fmt.Printf("Error reading example inputs from JSON: %s\n", e)
+		return 1
+	}
+
+	// Create the session with the test onnx network
+	session, e := onnxruntime.NewSimpleSession[float32](
+		"../test_data/example_network.onnx")
+	if e != nil {
+		fmt.Printf("Error initializing the ONNX session: %s\n", e)
+		return 1
+	}
+	defer session.Destroy()
+
+	// Create input and output tensors.
+	inputShape := onnxruntime.Shape(testInputs.InputShape)
+	outputShape := onnxruntime.Shape(testInputs.OutputShape)
+	inputTensor, e := onnxruntime.NewTensor(inputShape,
+		testInputs.FlattenedInput)
+	if e != nil {
+		fmt.Printf("Failed getting input tensor: %s\n", e)
+		return 1
+	}
+	defer inputTensor.Destroy()
+	outputTensor, e := onnxruntime.NewEmptyTensor[float32](outputShape)
+	if e != nil {
+		fmt.Printf("Failed creating output tensor: %s\n", e)
+		return 1
+	}
+	defer outputTensor.Destroy()
+
+	// Actually run the network.
+	e = session.SimpleRun(inputTensor, outputTensor)
+	if e != nil {
+		fmt.Printf("Failed running network: %s\n", e)
+		return 1
+	}
+
+	for i := range outputTensor.GetData() {
+		fmt.Printf("Output value %d: expected %f, got %f\n", i,
+			outputTensor.GetData()[i], testInputs.FlattenedOutput[i])
+	}
+
 	// Ordinarily, it is probably fine to call this using defer, but we do it
 	// here just so we can print a status message after the cleanup completes.
 	e = onnxruntime.CleanupEnvironment()