How to send input to System.console.readLine(...) in Junit?

Question

I have a main method I'd like to test.

I'm just wondering how to pass what the console.readLine(...) and console.readLine(...) is expecting from my Junit test - without refactoring main(...) - I'm using JMockit if that would be of use here - i.e. mocking out the System.console()?.

class MyClass {
    public static void main(String[] args) {
        Console console = System.console();

        String username = console.readLine("Enter your username: ");
        char[] newPassword = console.readPassword("Enter your new password: ");

        ...
    }
}

class MyJunitTest {
    @Test
    public void test() {
        MyClass.main(null);
        // here I'd just like to pass the username and password to the console?
    }
}

Answer 1

I got this to work using JMockit to mock the Console class:

  @Test
  public void test(
      @Mocked final System systemMock,
      @Mocked final Console consoleMock) {
    new NonStrictExpectations() {
      {
        System.console();
        result = consoleMock;

        consoleMock.readLine(anyString);
        result = "aUsername";

        consoleMock.readPassword(anyString);
        result = "aPassword";
      }
    };

    MyClass.main(null);
  }