@Before
  public void setUp() throws Exception {
    tempDir = Files.createTempDirectory("FileStoreTest").toFile();
    Properties props = new Properties();
    _fileCopyBasedReplicationConfig = new FileCopyBasedReplicationConfig(new VerifiableProperties(props));
    reserveFileDir = new File(tempDir, "reserve-files");
    StorageManagerMetrics storeManagerMetrics = new StorageManagerMetrics(new MetricRegistry());
    diskSpaceAllocator = new DiskSpaceAllocator(true, reserveFileDir, 0, storeManagerMetrics);
    diskSpaceAllocator.initializePool(
        Arrays.asList(new DiskSpaceRequirements(STORE_ID, SEGMENT_CAPACITY, SEGMENT_COUNT, 0)));
    fileStore = new FileStore(tempDir.getAbsolutePath(), diskSpaceAllocator);
    fileStore.start(SEGMENT_CAPACITY);
  }
Sets up the test environment before each test.
Creates temporary directory and initializes FileStore instance.
ambry-store/src/test/java/com/github/ambry/store/FileStoreTest.java