diff --git a/decor/moving_average.go b/decor/moving_average.go
index 50ac9c3..a1be8ad 100644
--- a/decor/moving_average.go
+++ b/decor/moving_average.go
@@ -5,6 +5,12 @@
 	"sync"
 
 	"github.com/VividCortex/ewma"
+)
+
+var (
+	_ ewma.MovingAverage = (*threadSafeMovingAverage)(nil)
+	_ ewma.MovingAverage = (*medianWindow)(nil)
+	_ sort.Interface     = (*medianWindow)(nil)
 )
 
 type threadSafeMovingAverage struct {