diff --git a/promql/testdata/histograms.test b/promql/testdata/histograms.test
index a9bb9b5e4..07e9a9225 100644
--- a/promql/testdata/histograms.test
+++ b/promql/testdata/histograms.test
@@ -15,6 +15,15 @@ load 5m
 	testhistogram_bucket{le="0.3", start="negative"}	0+2x10
 	testhistogram_bucket{le="+Inf", start="negative"}	0+3x10
 
+# Another test histogram, where q(1/6), q(1/2), and q(5/6) are each in
+# the middle of a bucket and should therefore be 1, 3, and 5,
+# respectively.
+load 5m
+	testhistogram2_bucket{le="0"}	 0+0x10
+	testhistogram2_bucket{le="2"}	 0+1x10
+	testhistogram2_bucket{le="4"}    0+2x10
+	testhistogram2_bucket{le="6"}	 0+3x10
+	testhistogram2_bucket{le="+Inf"} 0+3x10
 
 # Now a more realistic histogram per job and instance to test aggregation.
 load 5m
@@ -91,6 +100,25 @@ eval instant at 50m histogram_quantile(0.8, rate(testhistogram_bucket[5m]))
 	{start="positive"} 0.72
 	{start="negative"} 0.3
 
+# Want results exactly in the middle of the bucket.
+eval instant at 7m histogram_quantile(1./6., testhistogram2_bucket)
+	{} 1
+
+eval instant at 7m histogram_quantile(0.5, testhistogram2_bucket)
+	{} 3
+
+eval instant at 7m histogram_quantile(5./6., testhistogram2_bucket)
+	{} 5
+
+eval instant at 47m histogram_quantile(1./6., rate(testhistogram2_bucket[15m]))
+	{} 1
+
+eval instant at 47m histogram_quantile(0.5, rate(testhistogram2_bucket[15m]))
+	{} 3
+
+eval instant at 47m histogram_quantile(5./6., rate(testhistogram2_bucket[15m]))
+	{} 5
+
 # Aggregated histogram: Everything in one.
 eval instant at 50m histogram_quantile(0.3, sum(rate(request_duration_seconds_bucket[5m])) by (le))
 	{} 0.075