@Test
public void testToPrettyPrintingJson() {

  try {
    String expected = "{\n" +
        "  \"1\" : [ \"host2\", \"host3\" ],\n" +
        "  \"3\" : [ \"host1\" ]\n" +
        "}";
    assertEquals(expected, viewInfo.toPrettyPrintingJson());
  } catch (IOException e) {
    e.printStackTrace();
    fail("translating to pretty printing json raises exception: " + e.getMessage());
  }
}