TEST(Checksum, UUIDs) {
  StringVector checksums;
  for (unsigned i = 0, n = 1000; i < n; ++i) {
    checksums.push_back(checksum(toString(createUUID())));
  }
  auto itStart = checksums.begin();
  ++itStart;
  for (auto it = checksums.begin(), itEnd = checksums.end(); 
       itStart != itEnd; ++it, ++itStart) {
    EXPECT_TRUE(std::find(itStart,itEnd,*it) == itEnd);
  }
}