TF_EXPECT_OK(ReadCache(&cache, "", block_size, 1, &out));
  // Element at 0 was evicted again.
  calls.push_back(0);
  TF_EXPECT_OK(ReadCache(&cache, "", 0, 1, &out));
}

TEST(RamFileBlockCacheTest, MaxStaleness) {
  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);