Added new test

Author: rjtokenring

internal/iot/client_test.go

@@ -0,0 +1,41 @@
+package iot
+
+import (
+	"testing"
+
+	iotclient "github.com/arduino/iot-client-go/v3"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestJSON_UnknownFields_areAccepted(t *testing.T) {
+
+	cert := iotclient.ArduinoDevicev2Cert{}
+
+	// Add unknown fields to the JSON and verify that marshalling and unmarshalling works without raising error.
+	// This is useful when the API is extended with new fields and the client is not updated yet.
+	certJson := `{
+		"compressed": {
+			"not_after": "0001-01-01T00:00:00Z",
+			"not_before": "0001-01-01T00:00:00Z",
+			"serial": "",
+			"signature": "signature",
+			"signature_asn1_x": "",
+			"signature_asn1_y": ""
+		},
+		"der": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA",
+		"device_id": "123",
+		"enabled": true,
+		"href": "",
+		"id": "",
+		"pem": "-----BEGIN CERTIFICATE-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA",
+		"unknown_field": "value",
+		"unknown_field2": "value2",
+		"new_api_field": 2222
+	}`
+
+	err := cert.UnmarshalJSON([]byte(certJson))
+	if err != nil {
+		t.Errorf("UnmarshalJSON failed: %s", err)
+	}
+	assert.Equal(t, 3, len(cert.AdditionalProperties))
+}