1 files changed, 47 insertions, 0 deletions
diff --git a/devtools/client/debugger/test/mochitest/browser_dbg-preview-frame.js b/devtools/client/debugger/test/mochitest/browser_dbg-preview-frame.js
new file mode 100644
index 0000000000..8ca20bce53
--- /dev/null
+++ b/devtools/client/debugger/test/mochitest/browser_dbg-preview-frame.js
@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+// Test hovering in a selected frame
+
+"use strict";
+
+add_task(async function () {
+  const dbg = await initDebugger("doc-script-switching.html");
+
+  const found = findElement(dbg, "callStackBody");
+  is(found, null, "Call stack is hidden");
+
+  invokeInTab("firstCall");
+  await waitForPaused(dbg);
+
+  info("Preview a variable in the second frame");
+  clickElement(dbg, "frame", 2);
+  await waitForSelectedFrame(dbg, "firstCall");
+  await assertFunctionPreview(dbg, 8, 4, "secondCall()");
+
+  info("Preview should still work after selecting different locations");
+  const frame = dbg.selectors.getVisibleSelectedFrame();
+  const inScopeLines = dbg.selectors.getInScopeLines(frame.location);
+  await selectSource(dbg, "script-switching-01.js");
+  await assertFunctionPreview(dbg, 8, 4, "secondCall()");
+  is(
+    dbg.selectors.getInScopeLines(frame.location),
+    inScopeLines,
+    "In scope lines"
+  );
+});
+
+function waitForSelectedFrame(dbg, displayName) {
+  const { getInScopeLines, getVisibleSelectedFrame } = dbg.selectors;
+  return waitForState(dbg, state => {
+    const frame = getVisibleSelectedFrame();
+
+    return frame?.displayName == displayName && getInScopeLines(frame.location);
+  });
+}
+
+async function assertFunctionPreview(dbg, line, column, displayName) {
+  const previewEl = await tryHovering(dbg, line, column, "tooltip");
+  is(previewEl.innerText, displayName);
+}