}
  file_signature_map_[filename] = file_signature;
  return true;
}

size_t RamFileBlockCache::CacheSize() const {
  absl::MutexLock lock(&mu_);
  return cache_size_;
}

void RamFileBlockCache::Prune() {
  while (!stop_pruning_thread_.WaitForNotificationWithTimeout(
      absl::Microseconds(1000000))) {
    absl::MutexLock lock(&mu_);
    uint64_t now = timer_seconds_();
    while (!lra_list_.empty()) {

  EXPECT_EQ(out, a);
  EXPECT_EQ(calls, 5);
  TF_EXPECT_OK(ReadCache(&cache, "a", 8, n, &out));
  EXPECT_EQ(out, A);
  EXPECT_EQ(calls, 6);
}

TEST(RamFileBlockCacheTest, Prune) {
  int calls = 0;
  auto fetcher = [&calls](const string& filename, size_t offset, size_t n,
                          char* buffer, TF_Status* status) -> int64_t {
    calls++;
    memset(buffer, 'x', n);