Vfrdtyky

I'm using JUnit 5 and below I have two ChangeListeners on an IntegerProperty which one of them recursively changes the value of the property.

import javafx.beans.property.IntegerProperty;

import javafx.beans.property.SimpleIntegerProperty;

import javafx.beans.value.ChangeListener;

import javafx.beans.value.ObservableValue;

import org.junit.jupiter.api.Test;



import static org.hamcrest.MatcherAssert.assertThat;

import static org.hamcrest.Matchers.is;



public class FakeTest {

    @Test

    void testChangeListener() {

        IntegerProperty test = new SimpleIntegerProperty(0);

        test.addListener(new ChangeListener<Number>() {

            @Override

            public void changed(ObservableValue<? extends Number> observableValue, Number oldVal, Number newVal) {

                System.out.println("In first change listener: " + oldVal + " and " + newVal);

                if (newVal.intValue() < 5) {

                    test.setValue(test.getValue() + 1);

                }

            }

        });

        test.addListener(new ChangeListener<Number>() {

            @Override

            public void changed(ObservableValue<? extends Number> observableValue, Number oldVal, Number newVal) {

                // assertThat(newVal, is(oldVal.intValue() + 1));

                System.out.println("In second change listener: " + oldVal + " and " + newVal);

            }

        });

        test.setValue(1);

    }

}

I want to be able to assertThat(newVal, is(oldVal.intValue() + 1)); but for some reason the output is:

In first change listener: 0 and 1

In first change listener: 1 and 2

In first change listener: 2 and 3

In first change listener: 3 and 4

In first change listener: 4 and 5

In second change listener: 4 and 5

In second change listener: 3 and 5

In second change listener: 2 and 5

In second change listener: 1 and 5

In second change listener: 0 and 5

But I expect it to output:

In first change listener: 0 and 1

In first change listener: 1 and 2

In first change listener: 2 and 3

In first change listener: 3 and 4

In first change listener: 4 and 5

In second change listener: 0 and 1

In second change listener: 1 and 2

In second change listener: 2 and 3

In second change listener: 3 and 4

In second change listener: 4 and 5

I've done some research and I found ReactFX Var according to http://tomasmikula.github.io/blog/2015/02/10/val-a-better-observablevalue.html which says to fix the behaviour on recursive changes, but I'm not getting the desired output.

import javafx.beans.value.ChangeListener;

import javafx.beans.value.ObservableValue;

import org.junit.jupiter.api.Test;

import org.reactfx.value.Var;



import static org.hamcrest.MatcherAssert.assertThat;

import static org.hamcrest.Matchers.is;



public class FakeTest {

    @Test

    void testChangeListener() {

        Var<Integer> test = Var.newSimpleVar(0);

        test.addListener(new ChangeListener<Integer>() {

            @Override

            public void changed(ObservableValue<? extends Integer> observableValue, Integer oldVal, Integer newVal) {

                System.out.println("In first change listener: " + oldVal + " and " + newVal);

                if (newVal < 5) {

                    test.setValue(test.getValue() + 1);

                }

            }

        });

        test.addListener(new ChangeListener<Integer>() {

            @Override

            public void changed(ObservableValue<? extends Integer> observableValue, Integer oldVal, Integer newVal) {

                // assertThat(newVal, is(oldVal + 1));

                System.out.println("In second change listener: " + oldVal + " and " + newVal);

            }

        });

        test.setValue(1);

    }

}

Interestingly, I'm using IntelliJ and OpenJDK 11, but when I run the testChangeListener directly, I get the following output:

In first change listener: 0 and 1

In first change listener: 1 and 2

In first change listener: 2 and 3

In first change listener: 3 and 4

In first change listener: 4 and 5

In second change listener: 0 and 5

But when I click Run FakeTest (ie the whole test suite) I get:

In first change listener: 0 and 1

In second change listener: 0 and 2

In first change listener: 1 and 2

In second change listener: 2 and 3

In first change listener: 2 and 3

In second change listener: 3 and 4

In first change listener: 3 and 4

In second change listener: 4 and 5

In first change listener: 4 and 5

This is close to what I want, but again, I want something like:

In first change listener: 0 and 1

In second change listener: 0 and 1

In first change listener: 1 and 2

In second change listener: 1 and 2

In first change listener: 2 and 3

In second change listener: 2 and 3

In first change listener: 3 and 4

In second change listener: 3 and 4

In first change listener: 4 and 5

In second change listener: 4 and 5

1. How can I get the ChangeListeners to my expected output?


2. Why does the output change for Var when I choose to run the one test compared to the whole test suite? If I use IntegerProperty, I get the same output regardless of running the one test or the whole test suite.