### Question:
DeleteTransformationRule implements SchemaTransformationRule { @Override public Map<String, Object> transform(Map<String, Object> event) { return transform(event, key); } DeleteTransformationRule(List<String> key); @Override Map<String, Object> transform(Map<String, Object> event);  }### Answer:
@Test public void transformSimple() { Map<String, Object> event = new HashMap<>(); event.put("key", "value"); DeleteTransformationRule deleteRule = new DeleteTransformationRule(Arrays.asList("key")); Map<String, Object> result = deleteRule.transform(event); assertEquals(0, result.keySet().size()); }
@Test public void transformNested() { Map<String, Object> child = new HashMap<>(); child.put("child", "value"); Map<String, Object> event = new HashMap<>(); event.put("parent", child); DeleteTransformationRule deleteRule = new DeleteTransformationRule(Arrays.asList("parent", "child")); Map<String, Object> result = deleteRule.transform(event); assertEquals(1, result.keySet().size()); }