@Test
public void testMetrics_sendConfirmation_OnceSuccessful() {

    setNewMetrics();
    boolean isSent = confirmationServiceImpl.sendConfirmation(confirmationInfoMock_sent);
    assertTrue("send confirmation should be successful", isSent);
    double successRate = getSuccessRate();
    assertEquals(1.0, successRate, 0);
    assertEquals(1, getAllSent());
    assertEquals(0, getSentFailed());
}