1 files changed, 60 insertions, 0 deletions
diff --git a/layout/reftests/canvas/ctm-singular-sanity.html b/layout/reftests/canvas/ctm-singular-sanity.html
new file mode 100644
index 0000000000..48617d7628
--- /dev/null
+++ b/layout/reftests/canvas/ctm-singular-sanity.html
@@ -0,0 +1,60 @@
+<html>
+<head>
+  <script type="text/javascript">
+function assert(cond, msg) {
+  if (!cond) {
+    throw msg;
+  }
+}
+
+assert.equal = function(m1, m2, msg) {
+  assert(
+    m1.is2D &&
+      m2.is2D &&
+      m1.a === m2.a &&
+      m1.b === m2.b &&
+      m1.c === m2.c &&
+      m1.d === m2.d &&
+      m1.e === m2.e &&
+      m1.f === m2.f,
+    msg
+  );
+};
+
+window.onload = function() {
+  try {
+    var ctx = document.getElementById("c1").getContext("2d");
+
+    var singular = new DOMMatrix([0, 0, 0, 0, 0, 0]);
+    ctx.setTransform(singular);
+    assert.equal(
+      ctx.getTransform(),
+      singular,
+      "Expected setting transform to a singular matrix to work"
+    );
+    var inv = ctx.getTransform().invertSelf();
+    assert(
+      isNaN(inv.a) && isNaN(inv.b) && isNaN(inv.c) && isNaN(inv.d),
+      "Expected to get back matrix of NaN's from inverse transform"
+    );
+
+    var m = new DOMMatrix([1, 2, 3, 4, 5, 6]);
+    ctx.setTransform(m);
+    ctx.setTransform(singular.invertSelf());
+    assert.equal(
+      ctx.getTransform(),
+      m,
+      "Setting transform to an inverse singular matrix is a no-op"
+    );
+  } catch (e) {
+    document.body.innerHTML = "FAIL: " + e.toString();
+    return;
+  }
+  document.body.innerHTML = "Pass";
+};
+  </script>
+</head>
+<body>
+  <div><canvas id="c1" width="300" height="300"></canvas></div>
+</body>
+</html>