@Test
  public void testBackupWhileBucketIsCreated() throws Exception {
    vm0.invoke(() -> createRegions(vm0));

    // create a bucket on vm0
    vm0.invoke(() -> createData(0, 1, "A", regionName1));

    // create the pr on vm1, which won't have any buckets
    vm1.invoke(() -> createRegions(vm1));

    CompletableFuture<BackupStatus> backupStatusFuture =
        CompletableFuture.supplyAsync(() -> vm2.invoke(this::backupMember));

    CompletableFuture<Void> createDataFuture =
        CompletableFuture.runAsync(() -> vm0.invoke(() -> createData(1, 5, "A", regionName1)));

    CompletableFuture.allOf(backupStatusFuture, createDataFuture);

    BackupStatus status = backupStatusFuture.get();
    assertThat(status.getBackedUpDiskStores()).hasSize(2);
    assertThat(status.getOfflineDiskStores()).isEmpty();

    validateBackupComplete();

    vm0.invoke(() -> createData(0, 5, "C", regionName1));

    assertThat(status.getBackedUpDiskStores()).hasSize(2);
    assertThat(status.getOfflineDiskStores()).isEmpty();

    vm0.invoke(() -> getCache().close());
    vm1.invoke(() -> getCache().close());

    // destroy the current data
    cleanDiskDirsInEveryVM();

    restoreBackup(2);

    createPersistentRegions(vm0, vm1);

    vm0.invoke(() -> validateData(0, 1, "A", regionName1));

  }
Test for bug 42419

<p>
TRAC #42419: backed up disk stores map contains null key instead of member; cannot restore
backup files
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/backup/BackupDistributedTest.java