@After
  public void tearDown() throws Exception {
    EnvironmentEdgeManagerTestHelper.reset();
    LOG.info("Cleaning test directory: " + TEST_UTIL.getDataTestDir());
    TEST_UTIL.cleanupTestDir();
  }
Testing sync/append failures. Copied from TestHRegion.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestFailedAppendAndSync.java