1 files changed, 60 insertions, 0 deletions
diff --git a/devtools/client/inspector/rules/test/browser_rules_completion-on-empty.js b/devtools/client/inspector/rules/test/browser_rules_completion-on-empty.js
new file mode 100644
index 0000000000..9a3348783f
--- /dev/null
+++ b/devtools/client/inspector/rules/test/browser_rules_completion-on-empty.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests the suggest completion popup behavior of CSS property field.
+
+const TEST_URI = "<h1 style='color: lime'>Header</h1>";
+
+add_task(async function () {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  const { inspector, view } = await openRuleView();
+
+  info("Selecting the test node");
+  await selectNode("h1", inspector);
+
+  const prop = getTextProperty(view, 0, { color: "lime" });
+
+  info("Test with css property value field");
+  await testCompletion(view, prop.editor.valueSpan, true);
+
+  info("Test with css property name field");
+  await testCompletion(view, prop.editor.nameSpan, false);
+});
+
+async function testCompletion(view, target, isExpectedOpenPopup) {
+  const editor = await focusEditableField(view, target);
+
+  info(
+    "Check the suggest completion popup visibility after clearing the field"
+  );
+
+  const onChanged = view.once("ruleview-changed");
+  const popupEvent = isExpectedOpenPopup ? "popup-opened" : "popup-closed";
+  const onPopupEvent =
+    editor.popup.isOpen === isExpectedOpenPopup
+      ? Promise.resolve()
+      : once(view.popup, popupEvent);
+  EventUtils.synthesizeKey("VK_BACK_SPACE", {}, view.styleWindow);
+
+  // Flush the debounce to update the preview text.
+  view.debounce.flush();
+
+  await Promise.all([onChanged, onPopupEvent]);
+  is(
+    editor.popup.isOpen,
+    isExpectedOpenPopup,
+    "The popup visibility is correct"
+  );
+
+  if (editor.popup.isOpen) {
+    info("Close the suggest completion popup");
+    const closingEvents = [
+      view.once("ruleview-changed"),
+      once(view.popup, "popup-closed"),
+    ];
+    EventUtils.synthesizeKey("VK_ESCAPE", {}, view.styleWindow);
+    await Promise.all(closingEvents);
+  }
+}