From 9a179608cfda6fe24126b569e278553a775a4544 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 25 Jan 2023 10:27:06 -0500
Subject: [PATCH 01/20] test(NODE-4999): Convert issue repro to failing test

---
 .../read-write-concern/write_concern.test.ts  | 111 ++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 test/integration/read-write-concern/write_concern.test.ts

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
new file mode 100644
index 00000000000..aaa68b90229
--- /dev/null
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -0,0 +1,111 @@
+const { expect } = require('chai');
+const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
+
+const mock = require('../../tools/mongodb-mock/index');
+const { MongoClient, Collection, Db } = require('../../../src');
+
+describe('Write Concern', function() {
+  it('should respect writeConcern from uri', function(done) {
+    const client = this.configuration.newClient(
+      `${this.configuration.url()}&w=0&monitorCommands=true`
+    );
+    const events: any[] = [];
+    client.on('commandStarted', event => {
+      if (event.commandName === 'insert') {
+        events.push(event);
+      }
+    });
+
+    expect(client.writeConcern).to.eql({ w: 0 });
+    client
+      .db('test')
+      .collection('test')
+      .insertOne({ a: 1 }, (err, result) => {
+        expect(err).to.not.exist;
+        expect(result).to.exist;
+        expect(events).to.be.an('array').with.lengthOf(1);
+        expect(events[0]).to.containSubset({
+          commandName: 'insert',
+          command: {
+            writeConcern: { w: 0 }
+          }
+        });
+        client.close(done);
+      });
+  });
+
+  describe('mock server write concern test', () => {
+    let server;
+    before(() => {
+      return mock.createServer().then(s => {
+        server = s;
+      });
+    });
+
+    after(() => mock.cleanup());
+
+    // TODO: NODE-3816
+    it.skip('should pipe writeConcern from client down to API call', function() {
+      server.setMessageHandler(request => {
+        if (request.document && request.document[LEGACY_HELLO_COMMAND]) {
+          return request.reply(mock.HELLO);
+        }
+        expect(request.document.writeConcern).to.exist;
+        expect(request.document.writeConcern.w).to.equal('majority');
+        return request.reply({ ok: 1 });
+      });
+
+      const uri = `mongodb://${server.uri()}`;
+      const client = new MongoClient(uri, { writeConcern: 'majority' });
+      return client
+        .connect()
+        .then(() => {
+          const db = client.db('wc_test');
+          const collection = db.collection('wc');
+
+          return collection.insertMany([{ a: 2 }]);
+        })
+        .then(() => {
+          return client.close();
+        });
+    });
+  });
+
+  describe('must not affect read operations', function() {
+    let client: typeof MongoClient;
+    let db: typeof Db;
+    let col: typeof Collection;
+
+    beforeEach(async function() {
+      client = this.configuration.newClient({ 'writeConcern': { w: 0 } });
+      await client.connect();
+      db = client.db('test');
+      await db.dropCollection('writeConcernTest').catch(() => null);
+      col = db.collection('writeConcernTest');
+
+      const docs: any[] = [];
+      for (let i = 0; i < 1028; i++) {
+        docs.push({ a: i });
+      }
+
+      await col.insertMany(docs);
+    });
+
+    afterEach(async function() {
+      await client.close();
+    });
+
+    describe('when writeConcern=0', function() {
+      it('does not throw an error when getMore is called on cursor', async function() {
+        const findResult = col.find({});
+        let err;
+
+        await findResult.toArray()
+          .catch(e => {
+            err = e;
+          });
+        expect(err).to.not.exist;
+      });
+    });
+  });
+});

From dc466425c5933f38215af8e648d7338c467d32bd Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 25 Jan 2023 16:05:06 -0500
Subject: [PATCH 02/20] test(NODE-4999): Got repro working

---
 .../read-write-concern/write_concern.test.js  |  44 ++++++-
 .../read-write-concern/write_concern.test.ts  | 111 ------------------
 2 files changed, 40 insertions(+), 115 deletions(-)
 delete mode 100644 test/integration/read-write-concern/write_concern.test.ts

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 53d27500e45..050d92dfb60 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -1,10 +1,8 @@
-'use strict';
-
 const { expect } = require('chai');
-const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
 
-const mock = require('../../tools/mongodb-mock/index');
 const { MongoClient } = require('../../../src');
+const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
+const mock = require('../../tools/mongodb-mock/index');
 
 describe('Write Concern', function () {
   it('should respect writeConcern from uri', function (done) {
@@ -72,4 +70,42 @@ describe('Write Concern', function () {
         });
     });
   });
+
+  describe('must not affect read operations', function () {
+    let client;
+    let db;
+    let col;
+
+    beforeEach(async function () {
+      client = this.configuration.newClient({ writeConcern: { w: 0 } });
+      await client.connect();
+      db = client.db('test');
+      await db.dropCollection('writeConcernTest').catch(() => null);
+      col = db.collection('writeConcernTest');
+
+      const docs = [];
+      for (let i = 0; i < 1028; i++) {
+        docs.push({ a: i });
+      }
+
+      await col.insertMany(docs);
+    });
+
+    afterEach(async function () {
+      await client.close();
+    });
+
+    describe('when writeConcern=0', function () {
+      it('does not throw an error when getMore is called on cursor', async function () {
+        const findResult = col.find({});
+        let err;
+
+        await findResult.toArray().catch(e => {
+          throw e;
+        });
+
+        expect(err).to.not.exist;
+      });
+    });
+  });
 });
diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
deleted file mode 100644
index aaa68b90229..00000000000
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ /dev/null
@@ -1,111 +0,0 @@
-const { expect } = require('chai');
-const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
-
-const mock = require('../../tools/mongodb-mock/index');
-const { MongoClient, Collection, Db } = require('../../../src');
-
-describe('Write Concern', function() {
-  it('should respect writeConcern from uri', function(done) {
-    const client = this.configuration.newClient(
-      `${this.configuration.url()}&w=0&monitorCommands=true`
-    );
-    const events: any[] = [];
-    client.on('commandStarted', event => {
-      if (event.commandName === 'insert') {
-        events.push(event);
-      }
-    });
-
-    expect(client.writeConcern).to.eql({ w: 0 });
-    client
-      .db('test')
-      .collection('test')
-      .insertOne({ a: 1 }, (err, result) => {
-        expect(err).to.not.exist;
-        expect(result).to.exist;
-        expect(events).to.be.an('array').with.lengthOf(1);
-        expect(events[0]).to.containSubset({
-          commandName: 'insert',
-          command: {
-            writeConcern: { w: 0 }
-          }
-        });
-        client.close(done);
-      });
-  });
-
-  describe('mock server write concern test', () => {
-    let server;
-    before(() => {
-      return mock.createServer().then(s => {
-        server = s;
-      });
-    });
-
-    after(() => mock.cleanup());
-
-    // TODO: NODE-3816
-    it.skip('should pipe writeConcern from client down to API call', function() {
-      server.setMessageHandler(request => {
-        if (request.document && request.document[LEGACY_HELLO_COMMAND]) {
-          return request.reply(mock.HELLO);
-        }
-        expect(request.document.writeConcern).to.exist;
-        expect(request.document.writeConcern.w).to.equal('majority');
-        return request.reply({ ok: 1 });
-      });
-
-      const uri = `mongodb://${server.uri()}`;
-      const client = new MongoClient(uri, { writeConcern: 'majority' });
-      return client
-        .connect()
-        .then(() => {
-          const db = client.db('wc_test');
-          const collection = db.collection('wc');
-
-          return collection.insertMany([{ a: 2 }]);
-        })
-        .then(() => {
-          return client.close();
-        });
-    });
-  });
-
-  describe('must not affect read operations', function() {
-    let client: typeof MongoClient;
-    let db: typeof Db;
-    let col: typeof Collection;
-
-    beforeEach(async function() {
-      client = this.configuration.newClient({ 'writeConcern': { w: 0 } });
-      await client.connect();
-      db = client.db('test');
-      await db.dropCollection('writeConcernTest').catch(() => null);
-      col = db.collection('writeConcernTest');
-
-      const docs: any[] = [];
-      for (let i = 0; i < 1028; i++) {
-        docs.push({ a: i });
-      }
-
-      await col.insertMany(docs);
-    });
-
-    afterEach(async function() {
-      await client.close();
-    });
-
-    describe('when writeConcern=0', function() {
-      it('does not throw an error when getMore is called on cursor', async function() {
-        const findResult = col.find({});
-        let err;
-
-        await findResult.toArray()
-          .catch(e => {
-            err = e;
-          });
-        expect(err).to.not.exist;
-      });
-    });
-  });
-});

From 704e3fc75d53eb3e7aa8ff3be82233f9c310e740 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 26 Jan 2023 15:59:17 -0500
Subject: [PATCH 03/20] test(NODE-4999): Add tests to check for desired
 behaviour

---
 .../read-write-concern/write_concern.test.js  | 96 +++++++++++++------
 1 file changed, 69 insertions(+), 27 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 050d92dfb60..b7a55286de0 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -72,39 +72,81 @@ describe('Write Concern', function () {
   });
 
   describe('must not affect read operations', function () {
-    let client;
-    let db;
-    let col;
-
-    beforeEach(async function () {
-      client = this.configuration.newClient({ writeConcern: { w: 0 } });
-      await client.connect();
-      db = client.db('test');
-      await db.dropCollection('writeConcernTest').catch(() => null);
-      col = db.collection('writeConcernTest');
-
-      const docs = [];
-      for (let i = 0; i < 1028; i++) {
-        docs.push({ a: i });
-      }
+    describe('when writeConcern = 0', function () {
+      describe('does not throw an error when getMore is called on cursor', function () {
+        let client;
+        let db;
+        let col;
+
+        beforeEach(async function () {
+          client = this.configuration.newClient({ writeConcern: { w: 0 } });
+          await client.connect();
+          db = client.db('writeConcernTest');
+          col = db.collection('writeConcernTest');
+
+          const docs = [];
+          for (let i = 0; i < 10; i++) {
+            docs.push({ a: i, b: i + 1 });
+          }
 
-      await col.insertMany(docs);
-    });
+          await col.insertMany(docs);
+        });
 
-    afterEach(async function () {
-      await client.close();
-    });
+        afterEach(async function () {
+          await db.dropDatabase();
+          await client.close();
+        });
 
-    describe('when writeConcern=0', function () {
-      it('does not throw an error when getMore is called on cursor', async function () {
-        const findResult = col.find({});
-        let err;
+        it('find', async function () {
+          const findResult = col.find({}, { batchSize: 2 });
+          const err = await findResult.toArray().catch(e => e);
 
-        await findResult.toArray().catch(e => {
-          throw e;
+          expect(err).to.not.be.instanceOf(Error);
         });
 
-        expect(err).to.not.exist;
+        it('listCollections', async function () {
+          let collections = [];
+          for (let i = 0; i < 10; i++) {
+            collections.push(`writeConcernTestCol${i + 1}`);
+          }
+
+          for (const colName of collections) {
+            await db.createCollection(colName).catch(() => null);
+          }
+
+          const cols = db.listCollections({}, { batchSize: 2 });
+
+          const err = await cols.toArray().catch(e => e);
+
+          expect(err).to.not.be.instanceOf(Error);
+        });
+
+        it('aggregate', async function () {
+          const aggResult = col.aggregate([{ $match: { a: { $gte: 0 } } }], { batchSize: 2 });
+          const err = await aggResult.toArray().catch(e => e);
+
+          expect(err).to.not.be.instanceOf(Error);
+        });
+
+        it('listIndexes', async function () {
+          await col.createIndex({ a: 1 });
+          await col.createIndex({ b: -1 });
+          await col.createIndex({ a: 1, b: -1 });
+
+          const listIndexesResult = col.listIndexes({ batchSize: 2 });
+          const err = await listIndexesResult.toArray().catch(e => e);
+
+          expect(err).to.not.be.instanceOf(Error);
+        });
+
+        it('changeStream', async function () {
+          let changeStream = col.watch(undefined, { batchSize: 2 });
+          col.updateMany({}, [{ $addFields: { A: 1 } }]);
+
+          const err = await changeStream.next().catch(e => e);
+
+          expect(err).to.not.be.instanceOf(Error);
+        });
       });
     });
   });

From fa76f2d6f518267de89f041c8c4433287ebc7acd Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 26 Jan 2023 16:23:13 -0500
Subject: [PATCH 04/20] fix(NODE-4999): WIP fix

---
 src/operations/find.ts             | 3 ++-
 src/operations/list_collections.ts | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/operations/find.ts b/src/operations/find.ts
index 33aedd6b5f2..0f60e86d683 100644
--- a/src/operations/find.ts
+++ b/src/operations/find.ts
@@ -14,7 +14,8 @@ import { Aspect, defineAspects, Hint } from './operation';
  * @typeParam TSchema - Unused schema definition, deprecated usage, only specify `FindOptions` with no generic
  */
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
-export interface FindOptions<TSchema extends Document = Document> extends CommandOperationOptions {
+export interface FindOptions<TSchema extends Document = Document>
+  extends Omit<CommandOperationOptions, 'writeConcern'> {
   /** Sets the limit of documents returned in the query. */
   limit?: number;
   /** Set to sort the documents coming back from the query. Array of indexes, `[['a', 1]]` etc. */
diff --git a/src/operations/list_collections.ts b/src/operations/list_collections.ts
index ae1c15ec20f..2d01869726f 100644
--- a/src/operations/list_collections.ts
+++ b/src/operations/list_collections.ts
@@ -7,7 +7,7 @@ import { CommandOperation, CommandOperationOptions } from './command';
 import { Aspect, defineAspects } from './operation';
 
 /** @public */
-export interface ListCollectionsOptions extends CommandOperationOptions {
+export interface ListCollectionsOptions extends Omit<CommandOperationOptions, 'writeConcern'> {
   /** Since 4.0: If true, will only return the collection name in the response, and will omit additional info */
   nameOnly?: boolean;
   /** Since 4.0: If true and nameOnly is true, allows a user without the required privilege (i.e. listCollections action on the database) to run the command when access control is enforced. */

From 4d7ff6912511100acb079b4e579e471783cfddc9 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 14:26:56 -0500
Subject: [PATCH 05/20] fix(NODE-4999): Start implementing fix

---
 src/collection.ts                             |  1 +
 src/cursor/change_stream_cursor.ts            |  1 +
 src/operations/aggregate.ts                   |  2 ++
 src/operations/find.ts                        |  7 ++--
 src/operations/indexes.ts                     |  2 +-
 src/operations/list_collections.ts            |  4 +--
 src/operations/list_databases.ts              |  2 +-
 .../read-write-concern/write_concern.test.js  | 34 +++++++++++--------
 8 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/src/collection.ts b/src/collection.ts
index d61ffcb2855..1217ef0cccd 100644
--- a/src/collection.ts
+++ b/src/collection.ts
@@ -1524,6 +1524,7 @@ export class Collection<TSchema extends Document = Document> {
       options = pipeline;
       pipeline = [];
     }
+    options.writeConcern = undefined;
 
     return new ChangeStream<TLocal, TChange>(this, pipeline, resolveOptions(this, options));
   }
diff --git a/src/cursor/change_stream_cursor.ts b/src/cursor/change_stream_cursor.ts
index b5a4ae46307..4793234ebdb 100644
--- a/src/cursor/change_stream_cursor.ts
+++ b/src/cursor/change_stream_cursor.ts
@@ -143,6 +143,7 @@ export class ChangeStreamCursor<
     const aggregateOperation = new AggregateOperation(this.namespace, this.pipeline, {
       ...this.cursorOptions,
       ...this.options,
+      writeConcern: undefined,
       session
     });
 
diff --git a/src/operations/aggregate.ts b/src/operations/aggregate.ts
index a48a89ca5b2..5613b1ae163 100644
--- a/src/operations/aggregate.ts
+++ b/src/operations/aggregate.ts
@@ -101,6 +101,8 @@ export class AggregateOperation<T = Document> extends CommandOperation<T> {
 
     if (this.hasWriteStage && this.writeConcern) {
       Object.assign(command, { writeConcern: this.writeConcern });
+    } else {
+      Object.assign(this.options, { writeConcern: undefined });
     }
 
     if (options.bypassDocumentValidation === true) {
diff --git a/src/operations/find.ts b/src/operations/find.ts
index 0f60e86d683..7d39bfd64b5 100644
--- a/src/operations/find.ts
+++ b/src/operations/find.ts
@@ -119,6 +119,7 @@ export class FindOperation extends CommandOperation<Document> {
       {
         ...this.options,
         ...this.bsonOptions,
+        writeConcern: undefined,
         documentsReturnedIn: 'firstBatch',
         session
       },
@@ -142,9 +143,9 @@ function makeFindCommand(ns: MongoDBNamespace, filter: Document, options: FindOp
     if (projection && Array.isArray(projection)) {
       projection = projection.length
         ? projection.reduce((result, field) => {
-            result[field] = 1;
-            return result;
-          }, {})
+          result[field] = 1;
+          return result;
+        }, {})
         : { _id: 1 };
     }
 
diff --git a/src/operations/indexes.ts b/src/operations/indexes.ts
index 3a3b72dc30c..4e709d33c95 100644
--- a/src/operations/indexes.ts
+++ b/src/operations/indexes.ts
@@ -394,7 +394,7 @@ export class ListIndexesOperation extends CommandOperation<Document> {
   constructor(collection: Collection, options?: ListIndexesOptions) {
     super(collection, options);
 
-    this.options = options ?? {};
+    this.options = {...options, writeConcern: undefined} ?? {};
     this.collectionNamespace = collection.s.namespace;
   }
 
diff --git a/src/operations/list_collections.ts b/src/operations/list_collections.ts
index 2d01869726f..2249f63646e 100644
--- a/src/operations/list_collections.ts
+++ b/src/operations/list_collections.ts
@@ -7,7 +7,7 @@ import { CommandOperation, CommandOperationOptions } from './command';
 import { Aspect, defineAspects } from './operation';
 
 /** @public */
-export interface ListCollectionsOptions extends Omit<CommandOperationOptions, 'writeConcern'> {
+export interface ListCollectionsOptions extends CommandOperationOptions {
   /** Since 4.0: If true, will only return the collection name in the response, and will omit additional info */
   nameOnly?: boolean;
   /** Since 4.0: If true and nameOnly is true, allows a user without the required privilege (i.e. listCollections action on the database) to run the command when access control is enforced. */
@@ -28,7 +28,7 @@ export class ListCollectionsOperation extends CommandOperation<string[]> {
   constructor(db: Db, filter: Document, options?: ListCollectionsOptions) {
     super(db, options);
 
-    this.options = options ?? {};
+    this.options = { ...options, writeConcern: undefined } ?? {};
     this.db = db;
     this.filter = filter;
     this.nameOnly = !!this.options.nameOnly;
diff --git a/src/operations/list_databases.ts b/src/operations/list_databases.ts
index 537c9529037..d2255c34335 100644
--- a/src/operations/list_databases.ts
+++ b/src/operations/list_databases.ts
@@ -30,7 +30,7 @@ export class ListDatabasesOperation extends CommandOperation<ListDatabasesResult
 
   constructor(db: Db, options?: ListDatabasesOptions) {
     super(db, options);
-    this.options = options ?? {};
+    this.options = { ...options, writeConcern: undefined } ?? {};
     this.ns = new MongoDBNamespace('admin', '$cmd');
   }
 
diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index b7a55286de0..006352840ef 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -4,8 +4,8 @@ const { MongoClient } = require('../../../src');
 const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
 const mock = require('../../tools/mongodb-mock/index');
 
-describe('Write Concern', function () {
-  it('should respect writeConcern from uri', function (done) {
+describe('Write Concern', function() {
+  it('should respect writeConcern from uri', function(done) {
     const client = this.configuration.newClient(
       `${this.configuration.url()}&w=0&monitorCommands=true`
     );
@@ -45,7 +45,7 @@ describe('Write Concern', function () {
     after(() => mock.cleanup());
 
     // TODO: NODE-3816
-    it.skip('should pipe writeConcern from client down to API call', function () {
+    it.skip('should pipe writeConcern from client down to API call', function() {
       server.setMessageHandler(request => {
         if (request.document && request.document[LEGACY_HELLO_COMMAND]) {
           return request.reply(mock.HELLO);
@@ -71,40 +71,40 @@ describe('Write Concern', function () {
     });
   });
 
-  describe('must not affect read operations', function () {
-    describe('when writeConcern = 0', function () {
-      describe('does not throw an error when getMore is called on cursor', function () {
+  describe('must not affect read operations', function() {
+    describe('when writeConcern = 0', function() {
+      describe('does not throw an error when getMore is called on cursor', function() {
         let client;
         let db;
         let col;
 
-        beforeEach(async function () {
+        beforeEach(async function() {
           client = this.configuration.newClient({ writeConcern: { w: 0 } });
           await client.connect();
           db = client.db('writeConcernTest');
           col = db.collection('writeConcernTest');
 
           const docs = [];
-          for (let i = 0; i < 10; i++) {
+          for (let i = 0; i < 100; i++) {
             docs.push({ a: i, b: i + 1 });
           }
 
           await col.insertMany(docs);
         });
 
-        afterEach(async function () {
+        afterEach(async function() {
           await db.dropDatabase();
           await client.close();
         });
 
-        it('find', async function () {
+        it('find', async function() {
           const findResult = col.find({}, { batchSize: 2 });
           const err = await findResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listCollections', async function () {
+        it('listCollections', async function() {
           let collections = [];
           for (let i = 0; i < 10; i++) {
             collections.push(`writeConcernTestCol${i + 1}`);
@@ -121,14 +121,14 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('aggregate', async function () {
+        it('aggregate', async function() {
           const aggResult = col.aggregate([{ $match: { a: { $gte: 0 } } }], { batchSize: 2 });
           const err = await aggResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listIndexes', async function () {
+        it('listIndexes', async function() {
           await col.createIndex({ a: 1 });
           await col.createIndex({ b: -1 });
           await col.createIndex({ a: 1, b: -1 });
@@ -139,12 +139,16 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('changeStream', async function () {
+        it('changeStream', async function() {
           let changeStream = col.watch(undefined, { batchSize: 2 });
-          col.updateMany({}, [{ $addFields: { A: 1 } }]);
+
+          setTimeout(() => {
+            col.updateMany({}, [{ $addFields: { A: 1 } }]);
+          });
 
           const err = await changeStream.next().catch(e => e);
 
+
           expect(err).to.not.be.instanceOf(Error);
         });
       });

From 52f4cc552b6ba259dd6834cc4ee4590e136e3427 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 14:31:50 -0500
Subject: [PATCH 06/20] fix(NODE-4999): revert unneeded type change and run
 eslint

---
 src/operations/find.ts                        |  9 +++---
 src/operations/indexes.ts                     |  2 +-
 .../read-write-concern/write_concern.test.js  | 29 ++++++++++---------
 3 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/operations/find.ts b/src/operations/find.ts
index 7d39bfd64b5..55ca2141d04 100644
--- a/src/operations/find.ts
+++ b/src/operations/find.ts
@@ -14,8 +14,7 @@ import { Aspect, defineAspects, Hint } from './operation';
  * @typeParam TSchema - Unused schema definition, deprecated usage, only specify `FindOptions` with no generic
  */
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
-export interface FindOptions<TSchema extends Document = Document>
-  extends Omit<CommandOperationOptions, 'writeConcern'> {
+export interface FindOptions<TSchema extends Document = Document> extends CommandOperationOptions {
   /** Sets the limit of documents returned in the query. */
   limit?: number;
   /** Set to sort the documents coming back from the query. Array of indexes, `[['a', 1]]` etc. */
@@ -143,9 +142,9 @@ function makeFindCommand(ns: MongoDBNamespace, filter: Document, options: FindOp
     if (projection && Array.isArray(projection)) {
       projection = projection.length
         ? projection.reduce((result, field) => {
-          result[field] = 1;
-          return result;
-        }, {})
+            result[field] = 1;
+            return result;
+          }, {})
         : { _id: 1 };
     }
 
diff --git a/src/operations/indexes.ts b/src/operations/indexes.ts
index 4e709d33c95..8ae96eaefb7 100644
--- a/src/operations/indexes.ts
+++ b/src/operations/indexes.ts
@@ -394,7 +394,7 @@ export class ListIndexesOperation extends CommandOperation<Document> {
   constructor(collection: Collection, options?: ListIndexesOptions) {
     super(collection, options);
 
-    this.options = {...options, writeConcern: undefined} ?? {};
+    this.options = { ...options, writeConcern: undefined } ?? {};
     this.collectionNamespace = collection.s.namespace;
   }
 
diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 006352840ef..2f2888d8060 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -4,8 +4,10 @@ const { MongoClient } = require('../../../src');
 const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
 const mock = require('../../tools/mongodb-mock/index');
 
-describe('Write Concern', function() {
-  it('should respect writeConcern from uri', function(done) {
+const { setTimeout } = require('node:timers');
+
+describe('Write Concern', function () {
+  it('should respect writeConcern from uri', function (done) {
     const client = this.configuration.newClient(
       `${this.configuration.url()}&w=0&monitorCommands=true`
     );
@@ -45,7 +47,7 @@ describe('Write Concern', function() {
     after(() => mock.cleanup());
 
     // TODO: NODE-3816
-    it.skip('should pipe writeConcern from client down to API call', function() {
+    it.skip('should pipe writeConcern from client down to API call', function () {
       server.setMessageHandler(request => {
         if (request.document && request.document[LEGACY_HELLO_COMMAND]) {
           return request.reply(mock.HELLO);
@@ -71,14 +73,14 @@ describe('Write Concern', function() {
     });
   });
 
-  describe('must not affect read operations', function() {
-    describe('when writeConcern = 0', function() {
-      describe('does not throw an error when getMore is called on cursor', function() {
+  describe('must not affect read operations', function () {
+    describe('when writeConcern = 0', function () {
+      describe('does not throw an error when getMore is called on cursor', function () {
         let client;
         let db;
         let col;
 
-        beforeEach(async function() {
+        beforeEach(async function () {
           client = this.configuration.newClient({ writeConcern: { w: 0 } });
           await client.connect();
           db = client.db('writeConcernTest');
@@ -92,19 +94,19 @@ describe('Write Concern', function() {
           await col.insertMany(docs);
         });
 
-        afterEach(async function() {
+        afterEach(async function () {
           await db.dropDatabase();
           await client.close();
         });
 
-        it('find', async function() {
+        it('find', async function () {
           const findResult = col.find({}, { batchSize: 2 });
           const err = await findResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listCollections', async function() {
+        it('listCollections', async function () {
           let collections = [];
           for (let i = 0; i < 10; i++) {
             collections.push(`writeConcernTestCol${i + 1}`);
@@ -121,14 +123,14 @@ describe('Write Concern', function() {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('aggregate', async function() {
+        it('aggregate', async function () {
           const aggResult = col.aggregate([{ $match: { a: { $gte: 0 } } }], { batchSize: 2 });
           const err = await aggResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listIndexes', async function() {
+        it('listIndexes', async function () {
           await col.createIndex({ a: 1 });
           await col.createIndex({ b: -1 });
           await col.createIndex({ a: 1, b: -1 });
@@ -139,7 +141,7 @@ describe('Write Concern', function() {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('changeStream', async function() {
+        it('changeStream', async function () {
           let changeStream = col.watch(undefined, { batchSize: 2 });
 
           setTimeout(() => {
@@ -148,7 +150,6 @@ describe('Write Concern', function() {
 
           const err = await changeStream.next().catch(e => e);
 
-
           expect(err).to.not.be.instanceOf(Error);
         });
       });

From 877cd734ae784e42cdd3f200e40ee2bd679da737 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 15:02:04 -0500
Subject: [PATCH 07/20] test(NODE-4999): Fix import and extend timeout

---
 test/integration/read-write-concern/write_concern.test.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 2f2888d8060..5cc7ee93bbf 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -4,7 +4,7 @@ const { MongoClient } = require('../../../src');
 const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
 const mock = require('../../tools/mongodb-mock/index');
 
-const { setTimeout } = require('node:timers');
+const { setTimeout } = require('timers');
 
 describe('Write Concern', function () {
   it('should respect writeConcern from uri', function (done) {
@@ -146,7 +146,7 @@ describe('Write Concern', function () {
 
           setTimeout(() => {
             col.updateMany({}, [{ $addFields: { A: 1 } }]);
-          });
+          }, 500);
 
           const err = await changeStream.next().catch(e => e);
 

From 7f73b5ba3596a1c1b328771a58925f2b56f9d525 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 15:22:11 -0500
Subject: [PATCH 08/20] fix(NODE-4999): simplify changes

---
 src/change_stream.ts               | 2 +-
 src/collection.ts                  | 1 -
 src/cursor/change_stream_cursor.ts | 1 -
 src/operations/aggregate.ts        | 4 ++--
 src/operations/find.ts             | 3 +--
 src/operations/indexes.ts          | 2 +-
 src/operations/list_collections.ts | 2 +-
 src/operations/list_databases.ts   | 2 +-
 8 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/src/change_stream.ts b/src/change_stream.ts
index 7056f6d9dc6..44df28eb382 100644
--- a/src/change_stream.ts
+++ b/src/change_stream.ts
@@ -594,7 +594,7 @@ export class ChangeStream<
     super();
 
     this.pipeline = pipeline;
-    this.options = options;
+    this.options = { ...options, writeConcern: undefined };
 
     if (parent instanceof Collection) {
       this.type = CHANGE_DOMAIN_TYPES.COLLECTION;
diff --git a/src/collection.ts b/src/collection.ts
index 1217ef0cccd..d61ffcb2855 100644
--- a/src/collection.ts
+++ b/src/collection.ts
@@ -1524,7 +1524,6 @@ export class Collection<TSchema extends Document = Document> {
       options = pipeline;
       pipeline = [];
     }
-    options.writeConcern = undefined;
 
     return new ChangeStream<TLocal, TChange>(this, pipeline, resolveOptions(this, options));
   }
diff --git a/src/cursor/change_stream_cursor.ts b/src/cursor/change_stream_cursor.ts
index 4793234ebdb..b5a4ae46307 100644
--- a/src/cursor/change_stream_cursor.ts
+++ b/src/cursor/change_stream_cursor.ts
@@ -143,7 +143,6 @@ export class ChangeStreamCursor<
     const aggregateOperation = new AggregateOperation(this.namespace, this.pipeline, {
       ...this.cursorOptions,
       ...this.options,
-      writeConcern: undefined,
       session
     });
 
diff --git a/src/operations/aggregate.ts b/src/operations/aggregate.ts
index 5613b1ae163..79406b5e567 100644
--- a/src/operations/aggregate.ts
+++ b/src/operations/aggregate.ts
@@ -65,6 +65,8 @@ export class AggregateOperation<T = Document> extends CommandOperation<T> {
 
     if (this.hasWriteStage) {
       this.trySecondaryWrite = true;
+    } else {
+      this.options.writeConcern = undefined;
     }
 
     if (this.explain && this.writeConcern) {
@@ -101,8 +103,6 @@ export class AggregateOperation<T = Document> extends CommandOperation<T> {
 
     if (this.hasWriteStage && this.writeConcern) {
       Object.assign(command, { writeConcern: this.writeConcern });
-    } else {
-      Object.assign(this.options, { writeConcern: undefined });
     }
 
     if (options.bypassDocumentValidation === true) {
diff --git a/src/operations/find.ts b/src/operations/find.ts
index 55ca2141d04..f083942c160 100644
--- a/src/operations/find.ts
+++ b/src/operations/find.ts
@@ -77,7 +77,7 @@ export class FindOperation extends CommandOperation<Document> {
   ) {
     super(collection, options);
 
-    this.options = options;
+    this.options = { ...options, writeConcern: undefined };
     this.ns = ns;
 
     if (typeof filter !== 'object' || Array.isArray(filter)) {
@@ -118,7 +118,6 @@ export class FindOperation extends CommandOperation<Document> {
       {
         ...this.options,
         ...this.bsonOptions,
-        writeConcern: undefined,
         documentsReturnedIn: 'firstBatch',
         session
       },
diff --git a/src/operations/indexes.ts b/src/operations/indexes.ts
index 8ae96eaefb7..8005d931063 100644
--- a/src/operations/indexes.ts
+++ b/src/operations/indexes.ts
@@ -394,7 +394,7 @@ export class ListIndexesOperation extends CommandOperation<Document> {
   constructor(collection: Collection, options?: ListIndexesOptions) {
     super(collection, options);
 
-    this.options = { ...options, writeConcern: undefined } ?? {};
+    this.options = { ...options, writeConcern: undefined };
     this.collectionNamespace = collection.s.namespace;
   }
 
diff --git a/src/operations/list_collections.ts b/src/operations/list_collections.ts
index 2249f63646e..c432f1f1862 100644
--- a/src/operations/list_collections.ts
+++ b/src/operations/list_collections.ts
@@ -28,7 +28,7 @@ export class ListCollectionsOperation extends CommandOperation<string[]> {
   constructor(db: Db, filter: Document, options?: ListCollectionsOptions) {
     super(db, options);
 
-    this.options = { ...options, writeConcern: undefined } ?? {};
+    this.options = { ...options, writeConcern: undefined };
     this.db = db;
     this.filter = filter;
     this.nameOnly = !!this.options.nameOnly;
diff --git a/src/operations/list_databases.ts b/src/operations/list_databases.ts
index d2255c34335..537c9529037 100644
--- a/src/operations/list_databases.ts
+++ b/src/operations/list_databases.ts
@@ -30,7 +30,7 @@ export class ListDatabasesOperation extends CommandOperation<ListDatabasesResult
 
   constructor(db: Db, options?: ListDatabasesOptions) {
     super(db, options);
-    this.options = { ...options, writeConcern: undefined } ?? {};
+    this.options = options ?? {};
     this.ns = new MongoDBNamespace('admin', '$cmd');
   }
 

From 2c0a14dbeba53456ec55c01acf4c0f2640e7648b Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 15:39:43 -0500
Subject: [PATCH 09/20] test(NODE-4999): Ensure test only runs on replica sets
 and sharded clusters

---
 .../read-write-concern/write_concern.test.js   | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 5cc7ee93bbf..4e885476fc6 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -141,17 +141,19 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('changeStream', async function () {
-          let changeStream = col.watch(undefined, { batchSize: 2 });
+        if (client.options.replicaset) {
+          it('changeStream', async function () {
+            let changeStream = col.watch(undefined, { batchSize: 2 });
 
-          setTimeout(() => {
-            col.updateMany({}, [{ $addFields: { A: 1 } }]);
-          }, 500);
+            setTimeout(() => {
+              col.updateMany({}, [{ $addFields: { A: 1 } }]);
+            }, 500);
 
-          const err = await changeStream.next().catch(e => e);
+            const err = await changeStream.next().catch(e => e);
 
-          expect(err).to.not.be.instanceOf(Error);
-        });
+            expect(err).to.not.be.instanceOf(Error);
+          });
+        }
       });
     });
   });

From 82557e3cfab24859a6fed4d711eb875556ba8f96 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Fri, 27 Jan 2023 16:48:42 -0500
Subject: [PATCH 10/20] test(NODE-4999): conditionally execute test

---
 .../read-write-concern/write_concern.test.js           | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.js
index 4e885476fc6..e3a8f62bc3f 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.js
@@ -141,8 +141,8 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        if (client.options.replicaset) {
-          it('changeStream', async function () {
+        it('changeStream', async function () {
+          if (this.configuration.options.replicaSet) {
             let changeStream = col.watch(undefined, { batchSize: 2 });
 
             setTimeout(() => {
@@ -152,8 +152,10 @@ describe('Write Concern', function () {
             const err = await changeStream.next().catch(e => e);
 
             expect(err).to.not.be.instanceOf(Error);
-          });
-        }
+          } else {
+            this.skip();
+          }
+        });
       });
     });
   });

From 0f06672c5292a7a2e14e3acd5c28d39b32a69be7 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Mon, 30 Jan 2023 09:43:34 -0500
Subject: [PATCH 11/20] fix(NODE-4999): explicitly delete writeConcern key

---
 src/change_stream.ts               | 3 ++-
 src/operations/aggregate.ts        | 2 +-
 src/operations/find.ts             | 3 ++-
 src/operations/indexes.ts          | 3 ++-
 src/operations/list_collections.ts | 3 ++-
 5 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/change_stream.ts b/src/change_stream.ts
index 44df28eb382..42ee012785b 100644
--- a/src/change_stream.ts
+++ b/src/change_stream.ts
@@ -594,7 +594,8 @@ export class ChangeStream<
     super();
 
     this.pipeline = pipeline;
-    this.options = { ...options, writeConcern: undefined };
+    this.options = { ...options };
+    delete this.options.writeConcern;
 
     if (parent instanceof Collection) {
       this.type = CHANGE_DOMAIN_TYPES.COLLECTION;
diff --git a/src/operations/aggregate.ts b/src/operations/aggregate.ts
index 79406b5e567..9fb879c48e9 100644
--- a/src/operations/aggregate.ts
+++ b/src/operations/aggregate.ts
@@ -66,7 +66,7 @@ export class AggregateOperation<T = Document> extends CommandOperation<T> {
     if (this.hasWriteStage) {
       this.trySecondaryWrite = true;
     } else {
-      this.options.writeConcern = undefined;
+      delete this.options.writeConcern;
     }
 
     if (this.explain && this.writeConcern) {
diff --git a/src/operations/find.ts b/src/operations/find.ts
index f083942c160..87a6af88908 100644
--- a/src/operations/find.ts
+++ b/src/operations/find.ts
@@ -77,7 +77,8 @@ export class FindOperation extends CommandOperation<Document> {
   ) {
     super(collection, options);
 
-    this.options = { ...options, writeConcern: undefined };
+    this.options = { ...options };
+    delete this.options.writeConcern;
     this.ns = ns;
 
     if (typeof filter !== 'object' || Array.isArray(filter)) {
diff --git a/src/operations/indexes.ts b/src/operations/indexes.ts
index 8005d931063..31cef117a5d 100644
--- a/src/operations/indexes.ts
+++ b/src/operations/indexes.ts
@@ -394,7 +394,8 @@ export class ListIndexesOperation extends CommandOperation<Document> {
   constructor(collection: Collection, options?: ListIndexesOptions) {
     super(collection, options);
 
-    this.options = { ...options, writeConcern: undefined };
+    this.options = { ...options };
+    delete this.options.writeConcern;
     this.collectionNamespace = collection.s.namespace;
   }
 
diff --git a/src/operations/list_collections.ts b/src/operations/list_collections.ts
index c432f1f1862..a2a44f1d3db 100644
--- a/src/operations/list_collections.ts
+++ b/src/operations/list_collections.ts
@@ -28,7 +28,8 @@ export class ListCollectionsOperation extends CommandOperation<string[]> {
   constructor(db: Db, filter: Document, options?: ListCollectionsOptions) {
     super(db, options);
 
-    this.options = { ...options, writeConcern: undefined };
+    this.options = { ...options };
+    delete this.options.writeConcern;
     this.db = db;
     this.filter = filter;
     this.nameOnly = !!this.options.nameOnly;

From 2f0a3a6ac108a29faf3f76f201406158bb79a393 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Mon, 30 Jan 2023 09:57:40 -0500
Subject: [PATCH 12/20] test(NODE-4999): Convert test to typescript

---
 ..._concern.test.js => write_concern.test.ts} | 29 ++++++++++---------
 1 file changed, 15 insertions(+), 14 deletions(-)
 rename test/integration/read-write-concern/{write_concern.test.js => write_concern.test.ts} (86%)

diff --git a/test/integration/read-write-concern/write_concern.test.js b/test/integration/read-write-concern/write_concern.test.ts
similarity index 86%
rename from test/integration/read-write-concern/write_concern.test.js
rename to test/integration/read-write-concern/write_concern.test.ts
index e3a8f62bc3f..4292eaff2d7 100644
--- a/test/integration/read-write-concern/write_concern.test.js
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -1,17 +1,18 @@
-const { expect } = require('chai');
+import { expect } from 'chai';
+import { setTimeout } from 'timers';
 
-const { MongoClient } = require('../../../src');
-const { LEGACY_HELLO_COMMAND } = require('../../../src/constants');
-const mock = require('../../tools/mongodb-mock/index');
-
-const { setTimeout } = require('timers');
+import { Collection } from '../../../src/collection';
+import { LEGACY_HELLO_COMMAND } from '../../../src/constants';
+import { Db } from '../../../src/db';
+import { MongoClient } from '../../../src/mongo_client';
+import mock from '../../tools/mongodb-mock/index';
 
 describe('Write Concern', function () {
   it('should respect writeConcern from uri', function (done) {
     const client = this.configuration.newClient(
       `${this.configuration.url()}&w=0&monitorCommands=true`
     );
-    const events = [];
+    const events: any[] = [];
     client.on('commandStarted', event => {
       if (event.commandName === 'insert') {
         events.push(event);
@@ -58,7 +59,7 @@ describe('Write Concern', function () {
       });
 
       const uri = `mongodb://${server.uri()}`;
-      const client = new MongoClient(uri, { writeConcern: 'majority' });
+      const client = new MongoClient(uri, { writeConcern: { w: 'majority' } });
       return client
         .connect()
         .then(() => {
@@ -76,9 +77,9 @@ describe('Write Concern', function () {
   describe('must not affect read operations', function () {
     describe('when writeConcern = 0', function () {
       describe('does not throw an error when getMore is called on cursor', function () {
-        let client;
-        let db;
-        let col;
+        let client: MongoClient;
+        let db: Db;
+        let col: Collection;
 
         beforeEach(async function () {
           client = this.configuration.newClient({ writeConcern: { w: 0 } });
@@ -86,7 +87,7 @@ describe('Write Concern', function () {
           db = client.db('writeConcernTest');
           col = db.collection('writeConcernTest');
 
-          const docs = [];
+          const docs: any[] = [];
           for (let i = 0; i < 100; i++) {
             docs.push({ a: i, b: i + 1 });
           }
@@ -107,7 +108,7 @@ describe('Write Concern', function () {
         });
 
         it('listCollections', async function () {
-          let collections = [];
+          const collections: any[] = [];
           for (let i = 0; i < 10; i++) {
             collections.push(`writeConcernTestCol${i + 1}`);
           }
@@ -143,7 +144,7 @@ describe('Write Concern', function () {
 
         it('changeStream', async function () {
           if (this.configuration.options.replicaSet) {
-            let changeStream = col.watch(undefined, { batchSize: 2 });
+            const changeStream = col.watch(undefined, { batchSize: 2 });
 
             setTimeout(() => {
               col.updateMany({}, [{ $addFields: { A: 1 } }]);

From 164731c89948bc246c4f904208aa738a02d95da6 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Mon, 30 Jan 2023 11:12:17 -0500
Subject: [PATCH 13/20] fix(NODE-4999): ensure that copy is made of options
 object

---
 src/operations/aggregate.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/operations/aggregate.ts b/src/operations/aggregate.ts
index 9fb879c48e9..ea0b7fa4387 100644
--- a/src/operations/aggregate.ts
+++ b/src/operations/aggregate.ts
@@ -44,7 +44,7 @@ export class AggregateOperation<T = Document> extends CommandOperation<T> {
   constructor(ns: MongoDBNamespace, pipeline: Document[], options?: AggregateOptions) {
     super(undefined, { ...options, dbName: ns.db });
 
-    this.options = options ?? {};
+    this.options = { ...options };
 
     // Covers when ns.collection is null, undefined or the empty string, use DB_AGGREGATE_COLLECTION
     this.target = ns.collection || DB_AGGREGATE_COLLECTION;

From 9ab65497e5a3465296d4969a3cf14030fe9fa2ae Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Mon, 30 Jan 2023 11:13:38 -0500
Subject: [PATCH 14/20] test(NODE-4999): extend timeout for changeStream test
 and change find test to check for option deep equality

---
 test/integration/read-write-concern/write_concern.test.ts | 4 ++--
 test/unit/operations/find.test.ts                         | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 4292eaff2d7..b48def13bee 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -5,7 +5,7 @@ import { Collection } from '../../../src/collection';
 import { LEGACY_HELLO_COMMAND } from '../../../src/constants';
 import { Db } from '../../../src/db';
 import { MongoClient } from '../../../src/mongo_client';
-import mock from '../../tools/mongodb-mock/index';
+import * as mock from '../../tools/mongodb-mock/index';
 
 describe('Write Concern', function () {
   it('should respect writeConcern from uri', function (done) {
@@ -148,7 +148,7 @@ describe('Write Concern', function () {
 
             setTimeout(() => {
               col.updateMany({}, [{ $addFields: { A: 1 } }]);
-            }, 500);
+            }, 1000);
 
             const err = await changeStream.next().catch(e => e);
 
diff --git a/test/unit/operations/find.test.ts b/test/unit/operations/find.test.ts
index 43de87b617e..870541624b7 100644
--- a/test/unit/operations/find.test.ts
+++ b/test/unit/operations/find.test.ts
@@ -29,7 +29,7 @@ describe('FindOperation', function () {
     });
 
     it('sets options', function () {
-      expect(operation.options).to.equal(options);
+      expect(operation.options).to.deep.equal(options);
     });
 
     it('sets filter', function () {

From 2a26d173131700f60d91cf105e6fa7ffb80c04a6 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Mon, 30 Jan 2023 11:22:49 -0500
Subject: [PATCH 15/20] test(NODE-4999): Change test names and ensure that
 checks in find.test.ts test for deep equality

---
 .../read-write-concern/write_concern.test.ts     | 16 ++++++++--------
 test/unit/operations/find.test.ts                |  4 ++--
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index b48def13bee..f40c8641886 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -74,9 +74,9 @@ describe('Write Concern', function () {
     });
   });
 
-  describe('must not affect read operations', function () {
-    describe('when writeConcern = 0', function () {
-      describe('does not throw an error when getMore is called on cursor', function () {
+  context('when performing read operations', function () {
+    context('when writeConcern = 0', function () {
+      describe('cursor creating operations with a getMore', function () {
         let client: MongoClient;
         let db: Db;
         let col: Collection;
@@ -100,14 +100,14 @@ describe('Write Concern', function () {
           await client.close();
         });
 
-        it('find', async function () {
+        it('succeeds on find', async function () {
           const findResult = col.find({}, { batchSize: 2 });
           const err = await findResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listCollections', async function () {
+        it('succeeds on listCollections', async function () {
           const collections: any[] = [];
           for (let i = 0; i < 10; i++) {
             collections.push(`writeConcernTestCol${i + 1}`);
@@ -124,14 +124,14 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('aggregate', async function () {
+        it('succeeds on aggregate', async function () {
           const aggResult = col.aggregate([{ $match: { a: { $gte: 0 } } }], { batchSize: 2 });
           const err = await aggResult.toArray().catch(e => e);
 
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('listIndexes', async function () {
+        it('succeeds on listIndexes', async function () {
           await col.createIndex({ a: 1 });
           await col.createIndex({ b: -1 });
           await col.createIndex({ a: 1, b: -1 });
@@ -142,7 +142,7 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('changeStream', async function () {
+        it('succeeds on changeStream', async function () {
           if (this.configuration.options.replicaSet) {
             const changeStream = col.watch(undefined, { batchSize: 2 });
 
diff --git a/test/unit/operations/find.test.ts b/test/unit/operations/find.test.ts
index 870541624b7..9325341c57c 100644
--- a/test/unit/operations/find.test.ts
+++ b/test/unit/operations/find.test.ts
@@ -25,7 +25,7 @@ describe('FindOperation', function () {
     const operation = new FindOperation(undefined, namespace, filter, options);
 
     it('sets the namespace', function () {
-      expect(operation.ns).to.equal(namespace);
+      expect(operation.ns).to.deep.equal(namespace);
     });
 
     it('sets options', function () {
@@ -33,7 +33,7 @@ describe('FindOperation', function () {
     });
 
     it('sets filter', function () {
-      expect(operation.filter).to.equal(filter);
+      expect(operation.filter).to.deep.equal(filter);
     });
   });
 

From 17ebd06f14e4325f5204597b92ce72a2c178c247 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Tue, 31 Jan 2023 14:59:39 -0500
Subject: [PATCH 16/20] WIP

---
 test/integration/read-write-concern/write_concern.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index f40c8641886..b01bd571b27 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -146,9 +146,9 @@ describe('Write Concern', function () {
           if (this.configuration.options.replicaSet) {
             const changeStream = col.watch(undefined, { batchSize: 2 });
 
-            setTimeout(() => {
+            setImmediate(() => {
               col.updateMany({}, [{ $addFields: { A: 1 } }]);
-            }, 1000);
+            });
 
             const err = await changeStream.next().catch(e => e);
 

From d77a47b2d12c2756dc0276ba1d934b5cee0e6082 Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 1 Feb 2023 10:35:57 -0500
Subject: [PATCH 17/20] test(NODE-4999): Fix for failing ci test

---
 .../read-write-concern/write_concern.test.ts          | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index b01bd571b27..224ed2b439d 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -142,19 +142,18 @@ describe('Write Concern', function () {
           expect(err).to.not.be.instanceOf(Error);
         });
 
-        it('succeeds on changeStream', async function () {
-          if (this.configuration.options.replicaSet) {
+        it('succeeds on changeStream', {
+          metadata: { requires: { topology: 'replicaset' } },
+          async test() {
             const changeStream = col.watch(undefined, { batchSize: 2 });
 
-            setImmediate(() => {
+            setTimeout(() => {
               col.updateMany({}, [{ $addFields: { A: 1 } }]);
-            });
+            }, 1000);
 
             const err = await changeStream.next().catch(e => e);
 
             expect(err).to.not.be.instanceOf(Error);
-          } else {
-            this.skip();
           }
         });
       });

From 0c44d2a165f55c4a25efda6faed390e571a57ecb Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Wed, 1 Feb 2023 11:47:25 -0500
Subject: [PATCH 18/20] chore(NODE-4999): change mongo-client-encryption
 version

---
 .evergreen/run-tests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.evergreen/run-tests.sh b/.evergreen/run-tests.sh
index f24d2f166e3..b39576c5a86 100755
--- a/.evergreen/run-tests.sh
+++ b/.evergreen/run-tests.sh
@@ -52,7 +52,7 @@ else
   source "$DRIVERS_TOOLS"/.evergreen/csfle/set-temp-creds.sh
 fi
 
-npm install mongodb-client-encryption@"2.4.0-alpha.2"
+npm install mongodb-client-encryption@"2.4.0"
 npm install @mongodb-js/zstd
 npm install snappy
 

From c5050a893130216f7d7164ae88d9594c747c965c Mon Sep 17 00:00:00 2001
From: Warren James <warren.james@mongodb.com>
Date: Thu, 2 Feb 2023 14:13:32 -0500
Subject: [PATCH 19/20] test(NODE-4999): Fix changeStream test

---
 .../read-write-concern/write_concern.test.ts  | 31 ++++++++++++++-----
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 224ed2b439d..71c5ef63b3b 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -1,5 +1,5 @@
 import { expect } from 'chai';
-import { setTimeout } from 'timers';
+import { on, once } from 'events';
 
 import { Collection } from '../../../src/collection';
 import { LEGACY_HELLO_COMMAND } from '../../../src/constants';
@@ -146,13 +146,28 @@ describe('Write Concern', function () {
           metadata: { requires: { topology: 'replicaset' } },
           async test() {
             const changeStream = col.watch(undefined, { batchSize: 2 });
-
-            setTimeout(() => {
-              col.updateMany({}, [{ $addFields: { A: 1 } }]);
-            }, 1000);
-
-            const err = await changeStream.next().catch(e => e);
-
+            const changes = on(changeStream, 'change');
+            await once(changeStream.cursor, 'init');
+
+            await col.insertMany(
+              [
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 },
+                { a: 10 }
+              ],
+              { writeConcern: { w: 'majority' } }
+            );
+
+            const err = await changes.next().catch(e => e);
             expect(err).to.not.be.instanceOf(Error);
           }
         });

From b1c0c2ac861f6f4c63e91c767b38bad0d9df68cb Mon Sep 17 00:00:00 2001
From: Warren James <warren.james.dev@gmail.com>
Date: Thu, 2 Feb 2023 16:46:14 -0500
Subject: [PATCH 20/20] Update
 test/integration/read-write-concern/write_concern.test.ts

Co-authored-by: Neal Beeken <neal.beeken@mongodb.com>
---
 test/integration/read-write-concern/write_concern.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/integration/read-write-concern/write_concern.test.ts b/test/integration/read-write-concern/write_concern.test.ts
index 71c5ef63b3b..94cb2987689 100644
--- a/test/integration/read-write-concern/write_concern.test.ts
+++ b/test/integration/read-write-concern/write_concern.test.ts
@@ -47,7 +47,7 @@ describe('Write Concern', function () {
 
     after(() => mock.cleanup());
 
-    // TODO: NODE-3816
+    // TODO(NODE-3816): the mock server response is looking for writeConcern on all messages, but endSessions doesn't have it
     it.skip('should pipe writeConcern from client down to API call', function () {
       server.setMessageHandler(request => {
         if (request.document && request.document[LEGACY_HELLO_COMMAND]) {