test: fix reconnect tests for deno

Author: rexxars

test/helpers.ts

@@ -1,3 +1,4 @@
+import type {ServerResponse} from 'http'
 import sinon, {type SinonSpy} from 'sinon'
 
 import type {EventSourceClient} from '../src/types.js'
@@ -44,6 +45,47 @@ export function deferClose(es: EventSourceClient, timeout = 25): Promise<void> {
   return new Promise((resolve) => setTimeout(() => resolve(es.close()), timeout))
 }
 
+export async function waitForClose(res: ServerResponse): Promise<void> {
+  let resolve
+  let reject
+  const promise = new Promise<void>((_resolve, _reject) => {
+    resolve = _resolve
+    reject = _reject
+  })
+
+  let hasTimedOut = false
+  res.once('close', () => resolve())
+  const timeout = setTimeout(() => {
+    hasTimedOut = true
+    reject(new Error('Timeout waiting for close'))
+  }, 15000)
+
+  if (typeof globalThis.Deno === 'undefined') {
+    return promise
+  }
+
+  // Deno does not trigger close event, apparently, so we'll have to try to write,
+  // then catch the error that occurs upon a close
+  for (;;) {
+    if (hasTimedOut) {
+      return promise
+    }
+
+    try {
+      res.write(':\n')
+    } catch (err: unknown) {
+      if (err instanceof Error && err.message.includes('cannot close or enqueue')) {
+        clearTimeout(timeout)
+        resolve()
+        return promise
+      }
+      throw err
+    }
+
+    await new Promise((waitResolve) => setTimeout(waitResolve, 100))
+  }
+}
+
 export function expect(thing: unknown): {
   toBe(expected: unknown): void
   toBeLessThan(thanNum: number): void

test/server.ts

@@ -6,6 +6,7 @@ import {resolve as resolvePath} from 'node:path'
 import esbuild from 'esbuild'
 
 import {unicodeLines} from './fixtures.js'
+import {waitForClose} from './helpers.js'
 
 const isDeno = typeof globalThis.Deno !== 'undefined'
 const idedListeners = new Map<string, Set<ServerResponse>>()
@@ -113,7 +114,7 @@ async function writeCounter(req: IncomingMessage, res: ServerResponse) {
   res.end()
 }
 
-function writeIdentifiedListeners(req: IncomingMessage, res: ServerResponse) {
+async function writeIdentifiedListeners(req: IncomingMessage, res: ServerResponse) {
   const url = new URL(req.url || '/', 'http://localhost')
   const id = url.searchParams.get('id')
   if (!id) {
@@ -137,7 +138,9 @@ function writeIdentifiedListeners(req: IncomingMessage, res: ServerResponse) {
     })
     tryWrite(res, formatEvent({data: '', retry: 250}))
     tryWrite(res, formatEvent({data: `${idedListeners.size}`}))
-    res.on('close', () => (idedListeners.get(id) || new Set()).delete(res))
+
+    await waitForClose(res)
+    ;(idedListeners.get(id) || new Set()).delete(res)
     return
   }