1 files changed, 56 insertions, 0 deletions
diff --git a/devtools/client/inspector/boxmodel/test/browser_boxmodel_jump-to-rule-on-hover.js b/devtools/client/inspector/boxmodel/test/browser_boxmodel_jump-to-rule-on-hover.js
new file mode 100644
index 0000000000..74f382259e
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+++ b/devtools/client/inspector/boxmodel/test/browser_boxmodel_jump-to-rule-on-hover.js
@@ -0,0 +1,56 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that hovering over a box model value will jump to its source CSS rule in the
+// rules view when the shift key is pressed.
+
+const TEST_URI = `<style>
+    #box {
+      margin: 5px;
+    }
+  </style>
+  <div id="box"></div>`;
+
+add_task(async function () {
+  await pushPref("devtools.layout.boxmodel.highlightProperty", true);
+  await addTab("data:text/html," + encodeURIComponent(TEST_URI));
+  const { inspector, boxmodel } = await openLayoutView();
+  await selectNode("#box", inspector);
+
+  info(
+    "Test that hovering over margin-top value highlights the property in rules view."
+  );
+  const ruleView = await inspector.getPanel("ruleview").view;
+  const el = boxmodel.document.querySelector(
+    ".boxmodel-margin.boxmodel-top > span"
+  );
+
+  info("Wait for mouse to hover over margin-top element.");
+  const onHighlightProperty = ruleView.once("scrolled-to-element");
+  EventUtils.synthesizeMouseAtCenter(
+    el,
+    { type: "mousemove", shiftKey: true },
+    boxmodel.document.defaultView
+  );
+  await onHighlightProperty;
+
+  info("Check that margin-top is visible in the rule view.");
+  const { rules, styleWindow } = ruleView;
+  const marginTop = rules[1].textProps[0].computed[0];
+  ok(
+    isInViewport(marginTop.element, styleWindow),
+    "margin-top is visible in the rule view."
+  );
+});
+
+function isInViewport(element, win) {
+  const { top, left, bottom, right } = element.getBoundingClientRect();
+  return (
+    top >= 0 &&
+    bottom <= win.innerHeight &&
+    left >= 0 &&
+    right <= win.innerWidth
+  );
+}