* the tear-down for this test. Subsequent invocations of this method will return the same
   * directory.
   */
  protected final File getTempDir() throws IOException {
    if (tempDir == null) {
      tempDir = createTempDir();
    }

    return tempDir;
  }

  /**
   * Creates a new temp file in the temp directory returned by {@link #getTempDir()}. The file will
   * be deleted in the tear-down for this test.
   */