@Test
public void testSubstituteSimpleVars() throws Exception {

    Map<String, Object> fieldsAndValues = new HashMap<>();
    fieldsAndValues.put("1", "one");
    fieldsAndValues.put("2", "two");
    fieldsAndValues.put("3", "${1} plus ${2}");
    StreamlineEvent event = StreamlineEventImpl.builder().fieldsAndValues(fieldsAndValues).dataSourceId("dsrcid").build();
    TransformRuntime transformRuntime = new SubstituteTransformRuntime();
    List<StreamlineEvent> result = transformRuntime.execute(event);
    assertEquals(1, result.size());
    assertEquals(3, result.get(0).size());
    assertEquals("one", result.get(0).get("1"));
    assertEquals("two", result.get(0).get("2"));
    assertEquals("one plus two", result.get(0).get("3"));
}