private Path getBaseTestDir() {
    String PathName = System.getProperty(BASE_TEST_DIRECTORY_KEY, DEFAULT_BASE_TEST_DIRECTORY);

    return new Path(PathName);
  }
Returns Where to write test data on local filesystem; usually
{@link #DEFAULT_BASE_TEST_DIRECTORY} Should not be used by the unit tests, hence its's private.
Unit test will use a subdirectory of this directory.
@see #setupDataTestDir()
hbase-common/src/test/java/org/apache/hadoop/hbase/HBaseCommonTestingUtil.java