             layer.opacity = 1
             layer.tintColor = MTIColor(red: 1, green: 1, blue: 0, alpha: 1)
         })]
-        guard let outputImage = filter.outputImage else {
-            XCTFail()
-            return
-        }
+        let outputImage = try XCTUnwrap(filter.outputImage)
         let outputCGImage = try context.makeCGImage(from: outputImage)
         PixelEnumerator.enumeratePixels(in: outputCGImage) { (pixel, coord) in
             if coord.x == 0 && coord.y == 0 {

            }
        }
    }
    
    func testMultilayerCompositing_rotation() throws {
        guard let context = try makeContext() else { return }

            layer.size = CGSize(width: 1, height: 1)
            layer.opacity = 1
        })]
        let outputImage = try XCTUnwrap(filter.outputImage)
        let outputCGImage = try context.makeCGImage(from: outputImage)
        PixelEnumerator.enumeratePixels(in: outputCGImage) { (pixel, coord) in
            if coord.x == 0 && coord.y == 0 {
