1 files changed, 72 insertions, 0 deletions
diff --git a/devtools/server/tests/browser/browser_animation_emitMutations.js b/devtools/server/tests/browser/browser_animation_emitMutations.js
new file mode 100644
index 0000000000..796418c937
--- /dev/null
+++ b/devtools/server/tests/browser/browser_animation_emitMutations.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that the AnimationsActor emits events about changed animations on a
+// node after getAnimationPlayersForNode was called on that node.
+
+add_task(async function () {
+  const { target, walker, animations } = await initAnimationsFrontForUrl(
+    MAIN_DOMAIN + "animation.html"
+  );
+
+  info("Retrieve a non-animated node");
+  const node = await walker.querySelector(walker.rootNode, ".not-animated");
+
+  info("Retrieve the animation player for the node");
+  const players = await animations.getAnimationPlayersForNode(node);
+  is(players.length, 0, "The node has no animation players");
+
+  info("Listen for new animations");
+  let onMutations = once(animations, "mutations");
+
+  info("Add a couple of animation on the node");
+  await node.modifyAttributes([
+    { attributeName: "class", newValue: "multiple-animations" },
+  ]);
+  let changes = await onMutations;
+
+  ok(true, "The mutations event was emitted");
+  is(changes.length, 2, "There are 2 changes in the mutation event");
+  ok(
+    changes.every(({ type }) => type === "added"),
+    "Both changes are additions"
+  );
+
+  const names = changes.map(c => c.player.initialState.name).sort();
+  is(names[0], "glow", "The animation 'glow' was added");
+  is(names[1], "move", "The animation 'move' was added");
+
+  info("Store the 2 new players for comparing later");
+  const p1 = changes[0].player;
+  const p2 = changes[1].player;
+
+  info("Listen for removed animations");
+  onMutations = once(animations, "mutations");
+
+  info("Remove the animation css class on the node");
+  await node.modifyAttributes([
+    { attributeName: "class", newValue: "not-animated" },
+  ]);
+
+  changes = await onMutations;
+
+  ok(true, "The mutations event was emitted");
+  is(changes.length, 2, "There are 2 changes in the mutation event");
+  ok(
+    changes.every(({ type }) => type === "removed"),
+    "Both are removals"
+  );
+  ok(
+    changes[0].player === p1 || changes[0].player === p2,
+    "The first removed player was one of the previously added players"
+  );
+  ok(
+    changes[1].player === p1 || changes[1].player === p2,
+    "The second removed player was one of the previously added players"
+  );
+
+  await target.destroy();
+  gBrowser.removeCurrentTab();
+});