Function TestInconsistentHistogramCount

promql/engine_test.go:4593–4681

TestInconsistentHistogramCount is testing for https://github.com/prometheus/prometheus/issues/16681 which needs mixed integer and float histograms. The promql test framework only uses float histograms, so we cannot move this to promql tests.

(t *testing.T)

// integer and float histograms. The promql test framework only uses float
// histograms, so we cannot move this to promql tests.
func TestInconsistentHistogramCount(t *testing.T) {
	dir := t.TempDir()

	opts := tsdb.DefaultHeadOptions()
	opts.ChunkDirRoot = dir
	// We use TSDB head only. By using full TSDB DB, and appending samples to it, closing it would cause unnecessary HEAD compaction, which slows down the test.
	head, err := tsdb.NewHead(nil, nil, nil, nil, opts, nil)
	require.NoError(t, err)
	t.Cleanup(func() {
		_ = head.Close()
	})

	app := head.Appender(context.Background())

	l := labels.FromStrings("__name__", "series_1")

	mint := time.Now().Add(-time.Hour).UnixMilli()
	maxt := mint
	dT := int64(15 * 1000) // 15 seconds in milliseconds.
	inHs := []*histogram.Histogram{
		{
			Count: 2,
			Sum:   100,
			PositiveSpans: []histogram.Span{
				{Offset: 0, Length: 1},
			},
			PositiveBuckets: []int64{2},
		},
		{
			Count: 4,
			Sum:   200,
			PositiveSpans: []histogram.Span{
				{Offset: 0, Length: 1},
			},
			PositiveBuckets: []int64{4},
		},
		{}, // Empty histogram to trigger counter reset.
	}

	for i, h := range inHs {
		maxt = mint + dT*int64(i)
		_, err = app.AppendHistogram(0, l, maxt, h, nil)
		require.NoError(t, err)
	}

	require.NoError(t, app.Commit())
	queryable := storage.QueryableFunc(func(mint, maxt int64) (storage.Querier, error) {
		return tsdb.NewBlockQuerier(head, mint, maxt)
	})

	engine := promql.NewEngine(promql.EngineOpts{
		MaxSamples:    1000000,
		Timeout:       10 * time.Second,
		LookbackDelta: 5 * time.Minute,
	})

	var (
		query       promql.Query