test: release every gated response on teardown

A gate the test never releases, because an assertion failed before it got
there, leaves its route awaiting forever. Gates now register themselves
and an afterEach hook drains them, so this cannot be reintroduced by a
future test that forgets.

The reported hang does not reproduce: closing the browser destroys the
client socket, so the suspended route holds no live handle and the runner
exits. Forcing the assertion to fail reported the failure and exited in
seven seconds. The cleanup is worth having regardless.

Author: cardmagic

test/browser/reconnect.test.mjs

@@ -1,5 +1,5 @@
 import assert from "node:assert/strict"
-import { test, before, after, beforeEach } from "node:test"
+import { test, before, after, beforeEach, afterEach } from "node:test"
 import { startServer, openPage, loadPage, frameHtml } from "./browser_test_helper.mjs"
 
 // A reconnecting subscription replays the current state as a burst of refresh
@@ -14,6 +14,11 @@ let page
 const batches = new Map()
 const components = new Map()
 const cancelled = new Set()
+const gates = []
+
+function releaseGates() {
+  while (gates.length) gates.pop()()
+}
 
 before(async () => {
   const started = await startServer({
@@ -47,10 +52,15 @@ before(async () => {
 })
 
 after(async () => {
+  releaseGates()
   await browser?.close()
   server?.close()
 })
 
+afterEach(() => {
+  releaseGates()
+})
+
 beforeEach(async () => {
   batches.clear()
   components.clear()
@@ -67,11 +77,15 @@ async function waitFor(condition, message) {
   assert.fail(message)
 }
 
+// A gate a test forgets to release, because an assertion failed before it got
+// there, leaves its route awaiting forever and turns a reported failure into a
+// hung suite. Every gate is released when the test that made it finishes.
 function gate() {
   let release
   const promise = new Promise((resolve) => {
     release = resolve
   })
+  gates.push(release)
   return { promise, release }
 }