EXPECT_EQ(statistics.value().histogram_statistics().bin_width(), 2.f);
  // Trailing zeros should be removed.
  EXPECT_THAT(statistics.value().histogram_statistics().hist_freq(),
              ElementsAre(1, 0, 3, 5, 7, 6, 5));
}

TEST(HistogramStatisticsCollectorTest, AggregateSameBatchSize) {
  CalibrationOptions calib_opts;
  calib_opts.set_calibration_method(

    hist_stats = statistics.histogram_statistics
    self._bin_width = hist_stats.bin_width
    self._lower_bound = hist_stats.lower_bound
    self._hist_freq = np.array(hist_stats.hist_freq)
    self._num_bins = len(self._hist_freq)
    self._num_bits = 8
    # i-th bin has a range [bins[i], bins[i + 1]).
    # bins[i] = lower_bound + i * bin_width
    # bins[i + 1] = lower_bound + (i + 1) * bin_width

  ASSERT_TRUE(stats.has_histogram_statistics());
  EXPECT_FLOAT_EQ(stats.histogram_statistics().bin_width(), 0.5f);
  EXPECT_FLOAT_EQ(stats.histogram_statistics().lower_bound(), 1.f);
  EXPECT_THAT(stats.histogram_statistics().hist_freq(),
              ElementsAre(1, 4, 6, 7, 3, 2, 1));
}

TEST_F(CalibrationStatisticsSaverTest, MultipleStats) {
  std::vector<std::string> ids{"1", "2"};
  std::vector<int32_t> calibration_methods{