@Test
  public void testTransform() throws IOException {
    Object answer = Json.parseJson("{\"systems\": \"asd2\"}");
    var expression = Jsonata.jsonata("{'systems': 'asd2'}.$map($, $append(?))");
    Object evaluate = expression.evaluate(null);
    Assertions.assertEquals(answer, evaluate);
  }

  @Test
  public void testTransform2() {
    Object answer = Json.parseJson("{\"systems\": \"asd\"}");
    var expression = Jsonata.jsonata("$map($, $append(?))");
    Object evaluate = expression.evaluate(answer);
    Assertions.assertEquals(answer, evaluate);
  }

org.opentest4j.AssertionFailedError: 
Expected :{systems=asd2}
Actual   :[{systems=asd2}, 0]

org.opentest4j.AssertionFailedError: 
Expected :{systems=asd}
Actual   :[{systems=asd}, 0]