   
   func testTruncate() {
     let s = "Hello World"
-    
     XCTAssertTrue(s.truncate(at: 0) == "…")
     XCTAssertTrue(s.truncate(at: 0, withTrailing: nil) == "")
     XCTAssertTrue(s.truncate(at: 5) == "Hello…")

    XCTAssertTrue(string[Range(3..<3)] == "")
    XCTAssertTrue(string[Range(3..<6)] == "st😗")
    XCTAssertTrue(string[Range(0..<string.length)] == "∆Test😗🇮🇹")
    
    XCTAssertNil(string[Range(string.length ..< string.length+1)])
    XCTAssertTrue(string[Range(string.length ..< string.length)] == "")
    
    XCTAssertNil(string[Range(1 ..< 100)])
    XCTAssertNil(string[Range(-1 ..< 1)])
    XCTAssertNil(string[Range(1 ..< string.length+1)])

  }
  
  func testFirst(){
    XCTAssertTrue("Hello".first == "H")
    XCTAssertTrue("∂Hello".first == "∂")
    XCTAssertTrue(" Hello".first == " ")
  }
  
  func testLast(){
    XCTAssertTrue("Hello".last == "o")
    XCTAssertTrue("Hello∂".last == "∂")
    XCTAssertTrue("Hello ".last == " ")
  }
  
  func testRemovingPrefix() {
