         XCTAssertEqual(" AB".rtrimmed(), " AB")
         XCTAssertEqual("AB ".rtrimmed(), "AB")
         XCTAssertEqual("\n ABC   ".rtrimmed(), "\n ABC")
+        XCTAssertEqual("".rtrimmed(), "")
+        XCTAssertEqual(" \t\n\r".rtrimmed(), "")
     }
     
     func testLTrimmedForSet () {
         XCTAssertEqual("ab   ".ltrimmed(NSCharacterSet.alphanumericCharacterSet()), "   ")
         XCTAssertEqual("  ab".ltrimmed(NSCharacterSet.alphanumericCharacterSet()), "  ab")
+        XCTAssertEqual("ab".ltrimmed(NSCharacterSet.alphanumericCharacterSet()), "")
     }
     
     func testRTrimmedForSet () {
         XCTAssertEqual("ab   ".rtrimmed(NSCharacterSet.alphanumericCharacterSet()), "ab   ")
         XCTAssertEqual("  ab".rtrimmed(NSCharacterSet.alphanumericCharacterSet()), "  ")
+        XCTAssertEqual("ab".rtrimmed(NSCharacterSet.alphanumericCharacterSet()), "")
     }
 }

        XCTAssertEqual("t e".trimmed(), "t e")
        XCTAssertEqual(" AB".trimmed(), "AB")
        XCTAssertEqual("\n ABC   ".trimmed(), "ABC")
    }
    
    func testLTrimmed () {

        XCTAssertEqual("ab".ltrimmed(), "ab")
        XCTAssertEqual(" AB".ltrimmed(), "AB")
        XCTAssertEqual("\n ABC   ".ltrimmed(), "ABC   ")
        XCTAssertEqual("".ltrimmed(), "")
        XCTAssertEqual(" \t\n\r".ltrimmed(), "")
    }
    
    func testRTrimmed () {
