Package parity

Class ParityProbe

java.lang.Object

parity.ParityProbe

public class ParityProbe
extends Object

Every value that has to read the same on the desktop and in the browser.

The two implementations of this library have drifted apart more than once, and always in a way no signature could catch: a transparency that counted the other way round, a getWidth() that measured the rotated bounding box instead of the costume, a hitbox reported in screen pixels rather than around the middle of the stage. Every one of those was found by hand, by running the same program twice and reading the two outputs side by side. This is that program, written down.

Nothing here may depend on timing, randomness or the frame rate - the browser runs it in a different loop and would disagree for reasons that are not drift.

The expected output lives in src/test/resources/parity/expected.txt. ./scripts/parity.sh checks the desktop against it, and scripts/parity-fixture.py generates the copy the online IDE runs as ScratchParityTest.java in its own test suite.

Constructor Summary

Constructors

Constructor	Description
ParityProbe()

Method Summary

Modifier and Type	Method	Description
static void	main(String[] args)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ParityProbe

public ParityProbe()

Method Details

main

public static void main(String[] args)