third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-empty-image-source.html

<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script>
test(function() {
    var patternCanvas = new OffscreenCanvas(0, 50);
    var patternCanvasCtx = patternCanvas.getContext("2d");
    patternCanvasCtx.fillStyle = '#fed';
    patternCanvasCtx.fillRect(0, 0, 15, 15);
    var myOCanvas = new OffscreenCanvas(100, 100);
    var myOCanvasCtx = myOCanvas.getContext("2d");
    var pattern = myOCanvasCtx.createPattern(patternCanvas, 'repeat');
    myOCanvasCtx.fillStyle = pattern;
    myOCanvasCtx.fillRect(0, 0, myOCanvas.width, myOCanvas.height);
    var imageData = myOCanvasCtx.getImageData(0, 0, 1, 1).data;
    assert_equals(imageData[0], 0);
    assert_equals(imageData[1], 0);
    assert_equals(imageData[2], 0);
    assert_equals(imageData[3], 0);
}, "CreatePattern using OffcreenCanvas as image source silently fails when offscreenCanvas has zero size");
</script>