[time] UnixNano.Truncate should not panic on zero duration (#3571)

m3db · Jun 25, 2021 · 1c1a7ad · 1c1a7ad
1 parent 078564d
commit 1c1a7ad
Show file tree

Hide file tree

Showing 2 changed files with 14 additions and 0 deletions.
diff --git a/src/x/time/unix_nano.go b/src/x/time/unix_nano.go
@@ -39,7 +39,12 @@ func ToUnixNano(t time.Time) UnixNano {
 }
 
 // Truncate returns the result of rounding u down to a multiple of d.
+// If d <= 0, Truncate returns u unchanged.
 func (u UnixNano) Truncate(d time.Duration) UnixNano {
+	if d <= 0 {
+		return u
+	}
+
 	duration := UnixNano(d)
 	return (u / duration) * duration
 }

diff --git a/src/x/time/unix_nano_test.go b/src/x/time/unix_nano_test.go
@@ -70,3 +70,12 @@ func TestCompareTimes(t *testing.T) {
 	require.True(t, !UnixNano(0).Before(UnixNano(0)))
 	require.True(t, !UnixNano(0).After(UnixNano(0)))
 }
+
+func TestUnixNanoTruncate(t *testing.T) {
+	now := time.Unix(31415926, 42)
+	t0 := ToUnixNano(now)
+
+	require.Equal(t, ToUnixNano(now.Truncate(1*time.Second)), t0.Truncate(1*time.Second))
+	require.Equal(t, ToUnixNano(now.Truncate(0)), t0.Truncate(0))
+	require.Equal(t, ToUnixNano(now.Truncate(-10000)), t0.Truncate(-10000))
+}