diff --git a/test/public/tests.js b/test/public/tests.js
index c365200..f5720b5 100644
--- a/test/public/tests.js
+++ b/test/public/tests.js
@@ -1529,4 +1529,16 @@ tests['putImageData() CTM'] = function(ctx){
   ctx.translate(20,20);
   var data = ctx.getImageData(0,0,50,50);
   ctx.putImageData(data,60,60,10,20,35,30);
+};
+
+tests['putImageData() alpha'] = function(ctx){
+  ctx.fillStyle = 'rgba(255,0,0,0.5)'
+  ctx.fillRect(0,0,50,100);
+  ctx.fillStyle = 'rgba(0,255,0,0.5)'
+  ctx.fillRect(50,0,50,100);
+  ctx.fillStyle = 'rgba(0,0,255,0.5)'
+  ctx.fillRect(100,0,50,100);
+
+  var data = ctx.getImageData(0,0,120,20);
+  ctx.putImageData(data,20,120);
 };
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