@Test
public void testJSONFilterCode_lineNumberOnly() throws Exception {

  LOG.info("testJSONFilterCode_lineNumberOnly()");
  init(new HashMap<String, Object>());
  mockOutputManager.write(EasyMock.capture(capture), EasyMock.anyObject(InputMarker.class));
  EasyMock.expectLastCall();
  EasyMock.replay(mockOutputManager);
  filterJson.apply("{ line_number: 100, some_field: 'abc' }", new InputMarker(null, null, 0));
  EasyMock.verify(mockOutputManager);
  Map<String, Object> jsonParams = capture.getValue();
  assertEquals("Incorrect decoding: line number", 100l, jsonParams.remove("line_number"));
  assertEquals("Incorrect decoding: some field", "abc", jsonParams.remove("some_field"));
  assertTrue("jsonParams are not empty!", jsonParams.isEmpty());
}