diff --git a/src/test/java/org/apache/commons/imaging/formats/png/PngWriterTest.java b/src/test/java/org/apache/commons/imaging/formats/png/PngWriterTest.java
index 66b8d6f..ad759c6 100644
--- a/src/test/java/org/apache/commons/imaging/formats/png/PngWriterTest.java
+++ b/src/test/java/org/apache/commons/imaging/formats/png/PngWriterTest.java
@@ -75,7 +75,7 @@
 
         try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
             new PngWriter().writeImage(image, os, null, null);
-            byte[] bytes = os.toByteArray();
+            final byte[] bytes = os.toByteArray();
             final int numColors = countColors(bytes);
             assertTrue(numColors > 1);
         }