test: check-in before close

Author: nbbeeken

src/cmap/connection_pool.ts

@@ -492,10 +492,6 @@ export class ConnectionPool extends TypedEventEmitter<ConnectionPoolEvents> {
 
  closeCheckedOutConnections() {
  for (const conn of this.checkedOut) {
- this.emitAndLog(
- ConnectionPool.CONNECTION_CLOSED,
- new ConnectionClosedEvent(this, conn, 'poolClosed')
- );
  conn.onError(new MongoClientClosedError());
  }
  }

test/integration/connection-monitoring-and-pooling/connection_pool.test.ts

@@ -2,13 +2,7 @@ import { once } from 'node:events';
 
 import { expect } from 'chai';
 
-import {
- type ConnectionCheckedInEvent,
- type ConnectionCheckedOutEvent,
- type ConnectionPoolCreatedEvent,
- type Db,
- type MongoClient
-} from '../../mongodb';
+import { type ConnectionPoolCreatedEvent, type Db, type MongoClient } from '../../mongodb';
 import { clearFailPoint, configureFailPoint, sleep } from '../../tools/utils';
 
 describe('Connection Pool', function () {
@@ -104,10 +98,13 @@ describe('Connection Pool', function () {
  'a connection pool emits checked in events for closed connections',
  { requires: { mongodb: '>=4.4', topology: 'single' } },
  async () => {
- const connectionCheckedOutEvents: ConnectionCheckedOutEvent[] = [];
- client.on('connectionCheckedOut', event => connectionCheckedOutEvents.push(event));
- const connectionCheckedInEvents: ConnectionCheckedInEvent[] = [];
- client.on('connectionCheckedIn', event => connectionCheckedInEvents.push(event));
+ const allClientEvents = [];
+ const pushToClientEvents = e => allClientEvents.push(e);
+
+ client
+ .on('connectionCheckedOut', pushToClientEvents)
+ .on('connectionCheckedIn', pushToClientEvents)
+ .on('connectionClosed', pushToClientEvents);
 
  const inserts = Promise.allSettled([
  client.db('test').collection('test').insertOne({ a: 1 }),
@@ -116,19 +113,28 @@ describe('Connection Pool', function () {
  ]);
 
  // wait until all pings are pending on the server
- while (connectionCheckedOutEvents.length < 3) await sleep(1);
+ while (allClientEvents.filter(e => e.name === 'connectionCheckedOut').length < 3) {
+ await sleep(1);
+ }
 
- const insertConnectionIds = connectionCheckedOutEvents.map(
- ({ address, connectionId }) => `${address} + ${connectionId}`
- );
+ const insertConnectionIds = allClientEvents
+ .filter(e => e.name === 'connectionCheckedOut')
+  .map(({ address, connectionId }) => `${address} + ${connectionId}`);
 
  await client.close();
 
- const insertCheckIns = connectionCheckedInEvents.filter(({ address, connectionId }) =>
- insertConnectionIds.includes(`${address} + ${connectionId}`)
- );
+ const insertCheckInAndCloses = allClientEvents
+ .filter(e => e.name === 'connectionCheckedIn' || e.name === 'connectionClosed')
+ .filter(({ address, connectionId }) =>
+ insertConnectionIds.includes(`${address} + ${connectionId}`)
+ );
 
- expect(insertCheckIns).to.have.lengthOf(3);
+ expect(insertCheckInAndCloses).to.have.lengthOf(6);
+
+ // check that each check-in is followed by a close (not proceeded by one)
+ expect(insertCheckInAndCloses.map(e => e.name)).to.deep.equal(
+ Array.from({ length: 3 }, () => ['connectionCheckedIn', 'connectionClosed']).flat(1)
+ );
 
  await inserts;
  }