private void createPreviousFiles(final String name, final int mainId, final int fileCount,
      final int lineCount) throws IOException {
    int childId = 1;
    List<String> lines = lines(lineCount);
    for (int i = 0; i < fileCount; i++) {
      File file = createFile(name, mainId, childId);
      writeFile(file, lines);
      childId++;
    }
  }
Validates number of files under this.dir while ignoring this.dirOfDeletedFiles.
geode-core/src/integrationTest/java/org/apache/geode/internal/statistics/DiskSpaceLimitIntegrationTest.java