From 9da03955836f5703c7a6508d05ab352ac5cb8b68 Mon Sep 17 00:00:00 2001
From: Rosemary Yin <rosemaryy@users.noreply.github.com>
Date: Fri, 21 Jun 2019 16:39:31 -0400
Subject: [PATCH] fix(createCollection): Db.createCollection should pass
 readConcern to new collection (#2026)

* add tests to verify correct readConcern inheritance

* create new test for createCollection

* modernized test
---
 lib/db.js                            |  4 +++-
 lib/operations/create_collection.js  |  1 +
 test/functional/readconcern_tests.js | 27 ++++++++++++++++++++++++++-
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/lib/db.js b/lib/db.js
index 9f964fb2a5..5102ec17df 100644
--- a/lib/db.js
+++ b/lib/db.js
@@ -505,7 +505,9 @@ Db.prototype.createCollection = deprecateOptions(
     if (typeof options === 'function') (callback = options), (options = {});
     options = options || {};
     options.promiseLibrary = options.promiseLibrary || this.s.promiseLibrary;
-
+    options.readConcern = options.readConcern
+      ? new ReadConcern(options.readConcern.level)
+      : this.readConcern;
     const createCollectionOperation = new CreateCollectionOperation(this, name, options);
 
     return executeOperation(this.s.topology, createCollectionOperation, callback);
diff --git a/lib/operations/create_collection.js b/lib/operations/create_collection.js
index 055f7efccb..35c3a6f076 100644
--- a/lib/operations/create_collection.js
+++ b/lib/operations/create_collection.js
@@ -22,6 +22,7 @@ const illegalCommandFields = [
   'raw',
   'readPreference',
   'session',
+  'readConcern',
   'writeConcern'
 ];
 
diff --git a/test/functional/readconcern_tests.js b/test/functional/readconcern_tests.js
index 63b03866a4..3234542bb9 100644
--- a/test/functional/readconcern_tests.js
+++ b/test/functional/readconcern_tests.js
@@ -10,7 +10,7 @@ describe('ReadConcern', function() {
     return setupDatabase(configuration);
   });
 
-  it('Should set local readConcern on db level', {
+  it('Should set local readConcern on db level when using collection method', {
     metadata: { requires: { topology: 'replicaset', mongodb: '>= 3.2' } },
 
     test: function(done) {
@@ -56,6 +56,31 @@ describe('ReadConcern', function() {
     }
   });
 
+  it('Should set local readConcern on db level when using createCollection method', {
+    metadata: { requires: { topology: 'replicaset', mongodb: '>= 3.2' } },
+
+    test: function(done) {
+      // Get a new instance
+      const configuration = this.configuration;
+      const client = configuration.newClient(
+        { w: 1 },
+        { poolSize: 1, readConcern: { level: 'local' } }
+      );
+      client.connect((err, client) => {
+        expect(err).to.not.exist;
+        const db = client.db(configuration.db);
+        expect(db.s.readConcern).to.deep.equal({ level: 'local' });
+
+        // Get a collection using createCollection
+        db.createCollection('readConcernCollection', (err, collection) => {
+          // Validate readConcern
+          expect(collection.s.readConcern).to.deep.equal({ level: 'local' });
+          client.close(done);
+        });
+      });
+    }
+  });
+
   it('Should set majority readConcern on db level', {
     metadata: { requires: { topology: 'replicaset', mongodb: '>= 3.2' } },