来自InputStream的扫描仪输入

Question

I'm doing test driven development which requires me to write a test function for a class that takes input from the user. Since the console input function stops for input during tests, I wrote the tests using an InputStream which uses a string.

String str="3\n2\n1\n4\n";
InputStream is = new ByteArrayInputStream(str.getBytes());
assertTrue(app.RunApp(is));

This leads to the calling of the function getChoice(InputStream i) which involves console input from a Scanner.

public int getChoice(InputStream i) throws IOException {
        Scanner s=new Scanner(i);
        s.useDelimiter("\n");
        String y= s.next();
        int x=Integer.parseInt(y);
        return x;
    }

I want the above code to take the numbers in the string one by one. But, what is happening is that it takes the first number properly and then, the position of the stream goes directly to the end of the stream which causes a NoSuchElementException. Please Help!

Answer 1

采用...

String y = s.nextLine();  // That will take the entire line instead of only 1st word