         XCTAssertNil(info)
         
         info = string.reverseLines(in: string.nsRange)
-        XCTAssertEqual(info!.strings, ["ccc\nbbbb\naa"])
-        XCTAssertEqual(info!.ranges, [NSRange(0, 11)])
-        XCTAssertEqual(info!.selectedRanges, [NSRange(0, 11)])
+        XCTAssertEqual(info?.strings, ["ccc\nbbbb\naa"])
+        XCTAssertEqual(info?.ranges, [NSRange(0, 11)])
+        XCTAssertEqual(info?.selectedRanges, [NSRange(0, 11)])
         
         info = string.reverseLines(in: NSRange(2, 4))
-        XCTAssertEqual(info!.strings, ["bbbb\naa"])
-        XCTAssertEqual(info!.ranges, [NSRange(0, 7)])
-        XCTAssertEqual(info!.selectedRanges, [NSRange(0, 7)])
+        XCTAssertEqual(info?.strings, ["bbbb\naa"])
+        XCTAssertEqual(info?.ranges, [NSRange(0, 7)])
+        XCTAssertEqual(info?.selectedRanges, [NSRange(0, 7)])
     }
     
     

        XCTAssertNil(info)
        
        info = string.sortLinesAscending(in: string.nsRange)
        XCTAssertEqual(info!.strings, ["aa\nbbbb\nccc"])
        XCTAssertEqual(info!.ranges, [NSRange(0, 11)])
        XCTAssertEqual(info!.selectedRanges, [NSRange(0, 11)])
        
        info = string.sortLinesAscending(in: NSRange(2, 4))
        XCTAssertEqual(info!.strings, ["aa\nccc"])
        XCTAssertEqual(info!.ranges, [NSRange(0, 6)])
        XCTAssertEqual(info!.selectedRanges, [NSRange(0, 6)])
    }
    
    

        var info: String.EditingInfo?
        
        info = string.moveLineDown(in: [NSRange(4, 1)])
        XCTAssertEqual(info?.strings, ["aa\nccc\nbbbb\n"])
        XCTAssertEqual(info?.ranges, [NSRange(0, 12)])
        XCTAssertEqual(info?.selectedRanges, [NSRange(8, 1)])
        
        info = string.moveLineDown(in: [NSRange(4, 1), NSRange(6, 0)])
        XCTAssertEqual(info?.strings, ["aa\nccc\nbbbb\n"])
        XCTAssertEqual(info?.ranges, [NSRange(0, 12)])
        XCTAssertEqual(info?.selectedRanges, [NSRange(8, 1), NSRange(10, 0)])
        
        info = string.moveLineDown(in: [NSRange(4, 1), NSRange(9, 0), NSRange(13, 1)])
        XCTAssertEqual(info?.strings, ["aa\neee\nbbbb\nccc\nd"])
        XCTAssertEqual(info?.ranges, [NSRange(0, 17)])
        XCTAssertEqual(info?.selectedRanges, [NSRange(8, 1), NSRange(13, 0), NSRange(17, 1)])
        
        info = string.moveLineDown(in: [NSRange(14, 1)])
        XCTAssertNil(info)
