Swift: How do I test two OpenCV Mat for equality in swift

Question

How do I apply this answer how to check whether two matrices are identical in OpenCV to swift?

 let output = Mat(rows: input.rows(), cols: input.cols(), type: CvType.CV_8UC1)
 let test = Mat(rows: input.rows(), cols: input.cols(), type: CvType.CV_8UC1)
  ... fill test and output...
    if(!test.isSameMat(output)) {
        for x in 0 ..< output.rows() {
            for y in 0 ..< output.cols() {
                let value = output.get(row: x, col: y)
                let t = test.get(row: x, col: y)
                if t != value {
                    print("first mismatch row \(x) cols \(y)") <- this does not
                }
            }
        }
        assert(test.isSameMat(output)) <- this does trip for both isSameMat and isEqual
    }