1 files changed, 48 insertions, 0 deletions
diff --git a/devtools/client/inspector/animation/test/browser_animation_current-time-scrubber-with-negative-delay.js b/devtools/client/inspector/animation/test/browser_animation_current-time-scrubber-with-negative-delay.js
new file mode 100644
index 0000000000..8b2e177079
--- /dev/null
+++ b/devtools/client/inspector/animation/test/browser_animation_current-time-scrubber-with-negative-delay.js
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test whether the most left position means negative current time.
+
+add_task(async function () {
+  await addTab(URL_ROOT + "doc_multi_timings.html");
+  await removeAnimatedElementsExcept([
+    ".cssanimation-normal",
+    ".delay-negative",
+  ]);
+  const { animationInspector, panel, inspector } =
+    await openAnimationInspector();
+
+  info("Checking scrubber controller existence");
+  const controllerEl = panel.querySelector(".current-time-scrubber-area");
+  ok(controllerEl, "scrubber controller should exist");
+
+  info("Checking the current time of most left scrubber position");
+  const timeScale = animationInspector.state.timeScale;
+  clickOnCurrentTimeScrubberController(animationInspector, panel, 0);
+  await waitUntilAnimationsPlayState(animationInspector, "paused");
+  await waitUntilCurrentTimeChangedAt(
+    animationInspector,
+    -1 * timeScale.zeroPositionTime
+  );
+  ok(true, "Current time is correct");
+
+  info("Select negative current time animation");
+  await selectNode(".cssanimation-normal", inspector);
+  await waitUntilCurrentTimeChangedAt(
+    animationInspector,
+    -1 * timeScale.zeroPositionTime
+  );
+  ok(true, "Current time is correct");
+
+  info("Back to 'body' and rewind the animation");
+  await selectNode("body", inspector);
+  await waitUntil(
+    () =>
+      panel.querySelectorAll(".animation-item").length ===
+      animationInspector.state.animations.length
+  );
+  clickOnRewindButton(animationInspector, panel);
+  await waitUntilCurrentTimeChangedAt(animationInspector, 0);
+});