From 8c085513f8b63e48ed77408345f9d9a9c6f9afd2 Mon Sep 17 00:00:00 2001
From: Nan Deng <dengnan@google.com>
Date: Thu, 12 Jun 2014 15:38:52 -0700
Subject: [PATCH] fix a bug demostrated in TestPercentilesSmallDataSet()

---
 info/container.go      |  3 +++
 info/container_test.go | 24 +++++++++++++++++-------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/info/container.go b/info/container.go
index 16e47442..6fd67b46 100644
--- a/info/container.go
+++ b/info/container.go
@@ -238,6 +238,9 @@ func (self uint64Slice) Percentiles(requestedPercentiles ...int) []percentile {
 	sort.Sort(self)
 	for _, p := range requestedPercentiles {
 		idx := (len(self) * p / 100) - 1
+		if idx < 0 {
+			idx = 0
+		}
 		ret = append(
 			ret,
 			percentile{
diff --git a/info/container_test.go b/info/container_test.go
index fde9ab41..bf449a4e 100644
--- a/info/container_test.go
+++ b/info/container_test.go
@@ -80,13 +80,23 @@ func TestPercentiles(t *testing.T) {
 		if s.Value != uint64(s.Percentage) {
 			t.Errorf("%v percentile data should be %v, but got %v", s.Percentage, s.Percentage, s.Value)
 		}
-		/*
-			p := percentages[i]
-			d := uint64(N * p / 100)
-			if d != s {
-				t.Errorf("%v percentile data should be %v, but got %v", p, d, s)
-			}
-		*/
+	}
+}
+
+func TestPercentilesSmallDataSet(t *testing.T) {
+	var value uint64 = 11
+	data := []uint64{value}
+
+	percentages := []int{
+		80,
+		90,
+		50,
+	}
+	percentiles := uint64Slice(data).Percentiles(percentages...)
+	for _, s := range percentiles {
+		if s.Value != value {
+			t.Errorf("%v percentile data should be %v, but got %v", s.Percentage, value, s.Value)
+		}
 	}
 }