@Before
  public void createTestDirectory() {
    new File("target").mkdirs();
  }
Create the 'target' directory before the tests run. When running tests with multiple threads,
the working directory might be 'target/fork_#' which would changes the assumption that the
'target' directory exists already. When running tests via an IDE, the working directory might
be the project directory, and the target directory likely already exists.
iotdb-client/cli/src/test/java/org/apache/iotdb/tool/WriteDataFileTest.java