     XCTAssertEqual("Hell0W0rld".snakeCased(), "Hell0W0rld")
     XCTAssertEqual("HelloWorld".snakeCased(), "HelloWorld")
   }
-
+  
   func testSwapCased() {
     XCTAssertEqual("Hello World".swapCased(), "hELLO wORLD")
     XCTAssertEqual("hELLO wORLD".swapCased(), "Hello World")

    XCTAssert(range3! ~= string.index(string.startIndex, offsetBy: 2) ..< string.index(string.startIndex, offsetBy: 5))
    XCTAssertNil(string["k"])
    XCTAssertNil(string["123est"])

  }

  func testReplacingCharacters() {

    let s = "Hello World" //10 characters
    do {
      let countableRange = CountableRange(uncheckedBounds: (lower: 0, upper: 2)) //[0,2[
      let newString = s.replacingCharacters(in: countableRange, with: "1")
      XCTAssertTrue(newString == "1llo World")

      let countableClosedRange = CountableClosedRange(uncheckedBounds: (lower: 0, upper: 2)) //[0,2]
      let newString2 = s.replacingCharacters(in: countableClosedRange, with: "1")
      XCTAssertTrue(newString2 == "1lo World")

    XCTAssertEqual("Hell0W0rld".camelCased(), "hell0W0rld")
    XCTAssertEqual("helloWorld".camelCased(), "helloWorld")
  }
  
  func testKebabCased() {
    XCTAssertEqual("Hello World".kebabCased(), "-hello-world-")
    XCTAssertEqual("Hello_World".kebabCased(), "-hello-world-")
