How do simulate a button click in a swing pop up d

问题:

I'm new to Java, I want to write a JUnit test for a name validate class

I want to test the following code:

public boolean createNewUMLClassFromString(String className) {
    if(validate(className)){
              ....
    }
    return false;
}

private boolean validate(String userInput){
    /* check if it's empty  */
    if (userInput.equals("")){  
                    JOptionPane.showMessageDialog(null, "Class Name can't be empty");
        return false;
    }
            return true;
}

So I wrote a JUnit

public void emptyStringCheckerTest(){
    assertFalse("new class can not be empty", um.createNewUMLClassFromString("do"));

}

it works, but in the test running process, I need to click the pop up dialog every time.

So Is anyone can tell me how to simulate a button click in the test process, or Is there a better way to write the test? Thanks?

回答1:

To perform a programmatical button click, simply call the doClick() method. I don't know how to insert that into your testing procedure, though.

回答2:

Look at java.awt.Robot, and at libraries like abbot http://abbot.sourceforge.net/doc/overview.shtml that enhance it.

回答3:

Rewrite your validate method and move the JOptionPane call to a separate method which you can replace in your unit test (e.g. a package visible method).

private boolean validate(String userInput){
    /* check if it's empty  */
    if (userInput.equals("")){  
        showCannotBeEmptyDialog();            
        return false;
    }
            return true;
}

void showCannotBeEmptyDialog(){
  JOptionPane.showMessageDialog(null, "Class Name can't be empty");
}

Making it package visible still allows you to override it in your test (e.g. to not show a UI), and you still will be capable of asserting whether that method was actually called.

Another option would be to pass an instance as a constructor parameter which would be responsible for showing messages to the user. In your production code, this instance would use the JOptionPane class, where in your test you simply use a dummy. However, if it is just for showing one dialog this might be overkill.