Function testWriteTimestampWithTimezone

c++/test/TestWriter.cc:742–802

// function of setting timezone in Windows is different from Linux.
#ifndef _MSC_VER
  void testWriteTimestampWithTimezone(FileVersion fileVersion, const char* writerTimezone,
                                      const char* readerTimezone, const std::string& tsStr,
                                      int isDst = 0) {
    char* tzBk = getenv("TZ");  // backup TZ env

    MemoryOutputStream memStream(DEFAULT_MEM_STREAM_SIZE);
    MemoryPool* pool = getDefaultPool();
    std::unique_ptr<Type> type(Type::buildTypeFromString("struct<col1:timestamp>"));

    uint64_t stripeSize = 16 * 1024;
    uint64_t compressionBlockSize = 1024;
    uint64_t rowCount = 1;
    uint64_t memoryBlockSize = 64;

    std::unique_ptr<Writer> writer =
        createWriter(stripeSize, memoryBlockSize, compressionBlockSize, CompressionKind_ZLIB, *type,
                     pool, &memStream, fileVersion, 0, writerTimezone);
    auto batch = writer->createRowBatch(rowCount);
    auto& structBatch = dynamic_cast<StructVectorBatch&>(*batch);
    auto& tsBatch = dynamic_cast<TimestampVectorBatch&>(*structBatch.fields[0]);

    // write timestamp in the writer timezone
    setenv("TZ", writerTimezone, 1);
    tzset();
    struct tm tm;
    memset(&tm, 0, sizeof(struct tm));
    strptime(tsStr.c_str(), "%Y-%m-%d %H:%M:%S", &tm);
    // mktime() does depend on external hint for daylight saving time
    tm.tm_isdst = isDst;
    tsBatch.data[0] = mktime(&tm);
    tsBatch.nanoseconds[0] = 0;
    structBatch.numElements = rowCount;
    tsBatch.numElements = rowCount;
    writer->add(*batch);
    writer->close();

    // read timestamp from the reader timezone
    auto inStream = std::make_unique<MemoryInputStream>(memStream.getData(), memStream.getLength());
    std::unique_ptr<Reader> reader = createReader(pool, std::move(inStream));
    std::unique_ptr<RowReader> rowReader = createRowReader(reader.get(), readerTimezone);
    EXPECT_EQ(true, rowReader->next(*batch));

    // verify we get same wall clock in reader timezone
    setenv("TZ", readerTimezone, 1);
    tzset();
    memset(&tm, 0, sizeof(struct tm));
    time_t ttime = tsBatch.data[0];
    localtime_r(&ttime, &tm);
    char buf[20];
    strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", &tm);
    EXPECT_TRUE(strncmp(buf, tsStr.c_str(), tsStr.size()) == 0);

    // restore TZ env
    if (tzBk) {
      setenv("TZ", tzBk, 1);
      tzset();
    } else {
      unsetenv("TZ");