Null pointer when validating null values in JSON

[codemental]

A null pointer is caused when a JSON payload (expected or actual) contains 'null' as value. This is most probably caused by these lines:

expectedValueType := reflect.TypeOf(expectedValue)
actualValueType := reflect.TypeOf(actualValue)

The documentation states that if the argument of .TypeOf(...) is nil, the result is nil.

Here are example tests that fail:

func TestOKValidationWithNullValue(t *testing.T) {
	expectedValue := []byte("{" +
		"\"active\": null" +
		"}")

	actualValue := []byte("{" +
		"\"active\": null" +
		"}")

	// we ignore the recorder log because the order of the elements is always different
	testComparator(t, expectedValue, actualValue, []string{}, "")
}

func TestErrorValidationWithNullActualValue(t *testing.T) {
	expectedValue := []byte("{" +
		"\"active\": true" +
		"}")

	actualValue := []byte("{" +
		"\"active\": null" +
		"}")

	// we ignore the recorder log because the order of the elements is always different
	testComparator(t, expectedValue, actualValue, []string{}, "")
}

func TestErrorValidationWithNullExpectedValue(t *testing.T) {
	expectedValue := []byte("{" +
		"\"name\": null," +
		"}")

	actualValue := []byte("{" +
		" \"name\": \"Bruce Wayne\"," +
		"}")

	// we ignore the recorder log because the order of the elements is always different
	testComparator(t, expectedValue, actualValue, []string{}, "")
}

func TestNullExpectedValue(t *testing.T) {
	expectedErrors := []string{
		...
	}

	expectedValue := []byte("{" +
		"\"aliases\": [" +
		"null" +
		"]" +
		"}")
	actualValue := []byte("{" +
		"\"aliases\": [" +
		"\"Batman\"" +
		"]" +
		"}")

	expectedRecorderLog := "{\n" +
		"}\n"

	testComparator(t, expectedValue, actualValue, expectedErrors, expectedRecorderLog)
}

func TestNullActualValue(t *testing.T) {
	expectedErrors := []string{
		...
	}

	expectedValue := []byte("{" +
		"\"aliases\": [" +
		"\"Batman\"" +
		"]" +
		"}")
	actualValue := []byte("{" +
		"\"aliases\": [" +
		"null" +
		"]" +
		"}")

	expectedRecorderLog := "{\n" +
		"}\n"

	testComparator(t, expectedValue, actualValue, expectedErrors, expectedRecorderLog)
}