@Test
public void deliverStringDeliversToAppenderRef() {

    // given
    Appender appender = mock(Appender.class);
    when(appender.isStarted()).thenReturn(true);
    Configuration configuration = mock(Configuration.class);
    String testAppenderRef = "testAppenderRef";
    when(configuration.getAppender(testAppenderRef)).thenReturn(appender);
    FailoverPolicy<String> failoverPolicy = createTestFailoverPolicy(testAppenderRef, configuration);
    String failedMessage = UUID.randomUUID().toString();
    // when
    failoverPolicy.deliver(failedMessage);
    // then
    verify(appender, times(1)).append(any(LogEvent.class));
}