test: Customize image button's style

Author: oluwatobiss

src/ImageGallery.test.tsx

@@ -95,14 +95,18 @@ test("image gallery renders correctly with custom styles and fixed caption", ()
     position: "relative",
   };
 
+  const imageBtnStyle: React.CSSProperties = {
+    border: "4px solid purple",
+  };
+
   render(
     <ImageGallery
       imagesInfoArray={imagesArray}
       columnCount={1}
       columnWidth={300}
       gapSize={2}
       fixedCaption={true}
-      customStyles={{ imageContainerStyle }}
+      customStyles={{ imageContainerStyle, imageBtnStyle }}
     />
   );
 });