NSURL(string: "http://one/two;three/four")!.URLByAppendingPathComponent("five")
// This returns "http://one/two/five;three/four".

// Paths whose last component starts/ends with a dot (.) also have problems:
let url = NSURL(fileURLWithPath: "/path/to/.file")

// Expected: ???
// Actual: ""
let ext = url.pathExtension!

// Expected (based on pathExtension being ""): "/path/to/.file"
// Actual: "/path/to/"
url.URLByDeletingPathExtension!

// Expected: same as original URL
// Actual: "/path/to./"
url.URLByDeletingPathExtension!.URLByAppendingPathExtension(ext)

// <rdar://18421068>, only recently resolved in El Capitan, was a similar issue in NSURLComponents.