fix(tabs): lock automation to selected window

tests/message-router-window-lock.test.js

@@ -0,0 +1,91 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+
+const source = fs.readFileSync('background/message-router.js', 'utf8');
+
+function extractFunction(name) {
+  const markers = [`async function ${name}(`, `function ${name}(`];
+  const start = markers
+    .map((marker) => source.indexOf(marker))
+    .find((index) => index >= 0);
+  if (start < 0) {
+    throw new Error(`missing function ${name}`);
+  }
+
+  let parenDepth = 0;
+  let signatureEnded = false;
+  let braceStart = -1;
+  for (let index = start; index < source.length; index += 1) {
+    const ch = source[index];
+    if (ch === '(') parenDepth += 1;
+    if (ch === ')') {
+      parenDepth -= 1;
+      if (parenDepth === 0) signatureEnded = true;
+    }
+    if (ch === '{' && signatureEnded) {
+      braceStart = index;
+      break;
+    }
+  }
+
+  let depth = 0;
+  let end = braceStart;
+  for (; end < source.length; end += 1) {
+    const ch = source[end];
+    if (ch === '{') depth += 1;
+    if (ch === '}') {
+      depth -= 1;
+      if (depth === 0) {
+        end += 1;
+        break;
+      }
+    }
+  }
+
+  return source.slice(start, end);
+}
+
+test('message router locks automation window from sidepanel payload', async () => {
+  const bundle = [
+    extractFunction('normalizeAutomationWindowId'),
+    extractFunction('resolveAutomationWindowIdFromMessage'),
+    extractFunction('lockAutomationWindowFromMessage'),
+  ].join('\n');
+
+  const api = new Function(`
+const updates = [];
+async function setState(update) {
+  updates.push(update);
+}
+${bundle}
+return {
+  lockAutomationWindowFromMessage,
+  updates,
+};
+`)();
+
+  const windowId = await api.lockAutomationWindowFromMessage({
+    payload: { automationWindowId: 88 },
+  });
+
+  assert.equal(windowId, 88);
+  assert.deepEqual(api.updates, [{ automationWindowId: 88 }]);
+});
+
+test('message router can fall back to sender tab window id', async () => {
+  const bundle = [
+    extractFunction('normalizeAutomationWindowId'),
+    extractFunction('resolveAutomationWindowIdFromMessage'),
+  ].join('\n');
+
+  const api = new Function(`
+${bundle}
+return { resolveAutomationWindowIdFromMessage };
+`)();
+
+  assert.equal(
+    api.resolveAutomationWindowIdFromMessage({}, { tab: { windowId: 19 } }),
+    19
+  );
+});