protected String getSimpleTypeNodeTextValue(JsonNode jsonNode) {
        if (!isSimpleTypeNode(jsonNode)) {
            throw new IllegalArgumentException("Parameter does not contains a simple type");
        }
        return jsonNode.get(VALUE).textValue();
    }
@Test
    public void getSimpleTypeNodeTextValue_textNode() {
        ObjectNode jsonNode = new ObjectNode(factory);
        jsonNode.set(VALUE, new TextNode("testValue"));

        assertThat(expressionEvaluator.getSimpleTypeNodeTextValue(jsonNode)).isEqualTo("testValue");
    }