@Test
  public void testGetCacheXmlFile() {
    String fileName = "blah";
    Properties props = new Properties();
    // a loner is all this test needs
    props.setProperty(MCAST_PORT, "0");
    props.setProperty(LOCATORS, "");
    props.put(CACHE_XML_FILE, fileName);
    DistributionConfig config = createSystem(props).getConfig();
    assertThat(fileName).isEqualTo(config.getCacheXmlFile().getPath());
  }
Tests that getting the log level is what we expect.
geode-core/src/integrationTest/java/org/apache/geode/distributed/internal/InternalDistributedSystemIntegrationTest.java