diff --git a/promql/engine_test.go b/promql/engine_test.go
index 97633060c..41f12c547 100644
--- a/promql/engine_test.go
+++ b/promql/engine_test.go
@@ -3824,18 +3824,18 @@ histogram {{sum:4 count:4 buckets:[2 2]}} {{sum:6 count:6 buckets:[3 3]}} {{sum:
 		}
 	}
 
-	qry, err := engine.NewRangeQuery(context.Background(), storage, nil, "increase(histogram[60s])", time.Unix(0, 0), time.Unix(0, 0).Add(1*time.Minute), time.Minute)
+	qry, err := engine.NewRangeQuery(context.Background(), storage, nil, "increase(histogram[90s])", time.Unix(0, 0), time.Unix(0, 0).Add(60*time.Second), time.Minute)
 	require.NoError(t, err)
 	verify(t, qry, []histogram.FloatHistogram{
 		{
-			Count:           2,
-			Sum:             2,                                        // Increase from 4 to 6 is 2.
+			Count:           3,
+			Sum:             3,                                        // Increase from 4 to 6 is 2. Interpolation adds 1.
 			PositiveSpans:   []histogram.Span{{Offset: 0, Length: 2}}, // Two buckets changed between the first and second histogram.
-			PositiveBuckets: []float64{1, 1},                          // Increase from 2 to 3 is 1 in both buckets.
+			PositiveBuckets: []float64{1.5, 1.5},                      // Increase from 2 to 3 is 1 in both buckets. Interpolation adds 0.5.
 		},
 	})
 
-	qry, err = engine.NewInstantQuery(context.Background(), storage, nil, "histogram[60s]", time.Unix(0, 0).Add(2*time.Minute))
+	qry, err = engine.NewInstantQuery(context.Background(), storage, nil, "histogram[61s]", time.Unix(0, 0).Add(2*time.Minute))
 	require.NoError(t, err)
 	verify(t, qry, []histogram.FloatHistogram{
 		{
diff --git a/promql/promqltest/testdata/functions.test b/promql/promqltest/testdata/functions.test
index e1b44e41f..0d901ce01 100644
--- a/promql/promqltest/testdata/functions.test
+++ b/promql/promqltest/testdata/functions.test
@@ -799,7 +799,7 @@ load 10s
 eval instant at 1m sum_over_time(metric[2m])
   {} 2
 
-eval instant at 1m avg_over_time(metric[1m])
+eval instant at 1m avg_over_time(metric[2m])
   {} 0.5
 
 # Tests for stddev_over_time and stdvar_over_time.
diff --git a/promql/promqltest/testdata/native_histograms.test b/promql/promqltest/testdata/native_histograms.test
index 97eb200c5..8f917cf48 100644
--- a/promql/promqltest/testdata/native_histograms.test
+++ b/promql/promqltest/testdata/native_histograms.test
@@ -788,7 +788,7 @@ load 30s
     some_metric {{schema:0 sum:1 count:1 buckets:[1] counter_reset_hint:gauge}} {{schema:0 sum:2 count:2 buckets:[2] counter_reset_hint:gauge}} {{schema:0 sum:3 count:3 buckets:[3] counter_reset_hint:gauge}}
 
 # Test the case where we only have two points for rate
-eval_warn instant at 30s rate(some_metric[30s])
+eval_warn instant at 30s rate(some_metric[1m])
     {} {{count:0.03333333333333333 sum:0.03333333333333333 buckets:[0.03333333333333333]}}
 
 # Test the case where we have more than two points for rate
@@ -810,11 +810,11 @@ eval_warn instant at 1m30s rate(some_metric[1m])
     # Should produce no results.
 
 # Start with custom, end with exponential.
-eval_warn instant at 1m rate(some_metric[30s])
+eval_warn instant at 1m rate(some_metric[1m])
     # Should produce no results.
 
 # Start with exponential, end with custom.
-eval_warn instant at 30s rate(some_metric[30s])
+eval_warn instant at 30s rate(some_metric[1m])
     # Should produce no results.
 
 clear