Function TestSimpleAggregatorExemplarLimit

pkg/traceql/engine_metrics_test.go:2849–2897

TestSimpleAggregatorExemplarLimit verifies that SimpleAggregator (used in AggregateModeSum) respects req.Exemplars, including values above the old hardcoded limit of 100.

(t *testing.T)

// TestSimpleAggregatorExemplarLimit verifies that SimpleAggregator (used in AggregateModeSum)
// respects req.Exemplars, including values above the old hardcoded limit of 100.
func TestSimpleAggregatorExemplarLimit(t *testing.T) {
	tcs := []struct {
		name        string
		exemplars   uint32
		sendCount   int
		minExpected int // at least this many exemplars must appear in the result
	}{
		{"below_old_limit", 50, 200, 1},
		{"at_old_limit", 100, 200, 1},
		// Proves the fix: before the change, this was capped at 100.
		{"above_old_limit", 150, 200, 101},
		{"large", 200, 300, 1},
	}

	for _, tc := range tcs {
		t.Run(tc.name, func(t *testing.T) {
			req := &tempopb.QueryRangeRequest{
				Start:     uint64(1 * time.Second),
				End:       uint64(time.Duration(tc.sendCount+1) * time.Second),
				Step:      uint64(time.Second),
				Exemplars: tc.exemplars,
			}

			agg := NewSimpleCombiner(req, sumAggregation)

			// Build exemplars spread evenly across the time range (ms timestamps).
			startMs := req.Start / uint64(time.Millisecond)
			endMs := req.End / uint64(time.Millisecond)
			exemplars := make([]tempopb.Exemplar, tc.sendCount)
			for i := range exemplars {
				ts := startMs + uint64(i)*(endMs-startMs)/uint64(tc.sendCount)
				exemplars[i] = tempopb.Exemplar{TimestampMs: int64(ts), Value: float64(i)} //nolint: gosec // G115
			}

			agg.Combine([]*tempopb.TimeSeries{{
				Labels:    []commonv1proto.KeyValue{{Key: "service", Value: &commonv1proto.AnyValue{Value: &commonv1proto.AnyValue_StringValue{StringValue: "test"}}}},
				Samples:   []tempopb.Sample{{TimestampMs: int64(startMs), Value: 1.0}}, //nolint: gosec // G115
				Exemplars: exemplars,
			}})

			total := 0
			for _, ts := range agg.Results() {
				total += len(ts.Exemplars)
			}
			require.LessOrEqual(t, total, int(tc.exemplars), "exemplar count must not exceed req.Exemplars")
			require.GreaterOrEqual(t, total, tc.minExpected, "exemplar count must meet minimum expected")
		})
	}
}

func TestHistogramAggregator(t *testing.T) {
	req := &tempopb.QueryRangeRequest{