2d.layer.exceptions-are-no-op.tentative.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /html/canvas/element/layers/2d.layer.exceptions-are-no-op.tentative.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->

<meta charset="UTF-8">

<title>Canvas test: 2d.layer.exceptions-are-no-op.tentative</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="/html/canvas/resources/canvas-tests.js"></script>

<link rel="stylesheet" href="/html/canvas/resources/canvas-tests.css">

<body class="show_output">

<h1>2d.layer.exceptions-are-no-op.tentative</h1>

<p class="desc">Checks that the context state is left unchanged if beginLayer throws.</p>

<p class="output">Actual output:</p>

<canvas id="c" class="output" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>

<ul id="d"></ul>

<script>

test(t => {

  var canvas = document.getElementById('c');

  var ctx = canvas.getContext('2d');

  // Get `beginLayer` to throw while parsing the filter.

  assert_throws_js(TypeError,

                   () => ctx.beginLayer({filter: {name: 'colorMatrix',

                                                  values: 'foo'}}));

  // `beginLayer` shouldn't have opened the layer, so `endLayer` should throw.

  assert_throws_dom("InvalidStateError", () => ctx.endLayer());

}, "Checks that the context state is left unchanged if beginLayer throws.");

</script>