DefaultHealthCheckResults implements HealthCheckResults { public void addHealthCheckResult(HealthCheckResult result) { checkNotNull(result); _results.add(result); }  @Override boolean hasHealthyResult(); @Override Iterable<HealthCheckResult> getAllResults(); @Override HealthCheckResult getHealthyResult(); @Override Iterable<HealthCheckResult> getUnhealthyResults(); void addHealthCheckResult(HealthCheckResult result);  }
@Test(expected = NullPointerException.class) public void testNullResult() { _results.addHealthCheckResult(null); }