1 files changed, 55 insertions, 0 deletions
diff --git a/devtools/server/tests/browser/browser_animation_keepFinished.js b/devtools/server/tests/browser/browser_animation_keepFinished.js
new file mode 100644
index 0000000000..4f6b599da9
--- /dev/null
+++ b/devtools/server/tests/browser/browser_animation_keepFinished.js
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+
+"use strict";
+
+// Test that the AnimationsActor doesn't report finished animations as removed.
+// Indeed, animations that only have the "finished" playState can be modified
+// still, so we want the AnimationsActor to preserve the corresponding
+// AnimationPlayerActor.
+
+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");
+  let players = await animations.getAnimationPlayersForNode(node);
+  is(players.length, 0, "The node has no animation players");
+
+  info("Listen for new animations");
+  let reportedMutations = [];
+  function onMutations(mutations) {
+    reportedMutations = [...reportedMutations, ...mutations];
+  }
+  animations.on("mutations", onMutations);
+
+  info("Add a short animation on the node");
+  await node.modifyAttributes([
+    { attributeName: "class", newValue: "short-animation" },
+  ]);
+
+  info("Wait for longer than the animation's duration");
+  await wait(2000);
+
+  players = await animations.getAnimationPlayersForNode(node);
+  is(players.length, 0, "The added animation is surely finished");
+
+  is(reportedMutations.length, 1, "Only one mutation was reported");
+  is(reportedMutations[0].type, "added", "The mutation was an addition");
+
+  animations.off("mutations", onMutations);
+
+  await target.destroy();
+  gBrowser.removeCurrentTab();
+});
+
+function wait(ms) {
+  return new Promise(resolve => {
+    setTimeout(resolve, ms);
+  });
+}