### Question:
Log4jConfigurator implements Log4jConfiguratorMXBean { @Override public void setLogLevel(String logger, String level) { if (StringUtils.isNotBlank(logger) && StringUtils.isNotBlank(level)) { Logger log = getLogger(logger); if (log != null) { log.setLevel(Level.toLevel(level.toUpperCase())); } } }  @Override List<String> getLoggers(); @Override String getLogLevel(String logger); @Override void setLogLevel(String logger, String level);  }### Answer:
@Test public void testSetLogLevel() throws Exception { doReturn(logger("a", "INFO")).when(sut).getLogger("a"); sut.setLogLevel("a", "DEBUG"); assertEquals(sut.getLogLevel("a"), "DEBUG"); }