 /// :param: s2 Second string used in generation of firstDifferenceResult
 ///
 /// :returns: a printable string, possibly containing significant whitespace and newlines
-public func prettyDescriptionOfFirstDifferenceResult(_ firstDifferenceResult: FirstDifferenceResult, _ s1: NSString, _ s2: NSString) -> String {
-
-    func diffString(_ index: Int, _ s1: NSString, _ s2: NSString) -> String {
+public func prettyDescriptionOfFirstDifferenceResult(
+  _ firstDifferenceResult: FirstDifferenceResult,
+  _ s1: String,
+  _ s2: String
+) -> String {
+    func diffString(_ index: Int, _ s1: String, _ s2: String) -> String {
         let markerArrow = "👉"
         let ellipsis    = "…"
         /// Given a string and a range, return a string representing that substring.


    if translate != expected {
        //Find text difference
        let difference = prettyFirstDifferenceBetweenStrings(translate as NSString, expected as NSString)
        XCTFail(difference)
    }
}

/// Result type for firstDifferenceBetweenStrings()
public enum FirstDifferenceResult {
    /// Strings are identical
    case noDifference

    /// Strings differ at the specified index.
    ///
    /// This could mean that characters at the specified index are different,
    /// or that one string is longer than the other
    case differenceAtIndex(Int)
}
