@Test
public void testGetJson() throws IOException {

  tracker.addReport("node1", "node2");
  tracker.addReport("node2", "node3");
  tracker.addReport("node2", "node1");
  tracker.addReport("node4", "node1");
  final Set<ReportForJson> reports = getAndDeserializeJson();
  // And ensure its contents are what we expect.
  assertThat(reports.size(), is(3));
  assertTrue(isNodeInReports(reports, "node1"));
  assertTrue(isNodeInReports(reports, "node2"));
  assertTrue(isNodeInReports(reports, "node4"));
  assertFalse(isNodeInReports(reports, "node3"));
}