diff --git a/lib/sender.js b/lib/sender.js
index 5ea2986ee..c81ec66f6 100644
--- a/lib/sender.js
+++ b/lib/sender.js
@@ -80,7 +80,12 @@ class Sender {
         options.generateMask(mask);
       } else {
         if (randomPoolPointer === RANDOM_POOL_SIZE) {
+          /* istanbul ignore else  */
           if (randomPool === undefined) {
+            //
+            // This is lazily initialized because server-sent frames must not
+            // be masked so it may never be used.
+            //
             randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
           }
 
diff --git a/test/receiver.test.js b/test/receiver.test.js
index 88a6326d1..1f9e75d3a 100644
--- a/test/receiver.test.js
+++ b/test/receiver.test.js
@@ -1127,7 +1127,7 @@ describe('Receiver', () => {
     receiver.on('ping', listener);
     receiver.on('pong', listener);
 
-    receiver.write(Buffer.from('8101318901328a0133810134', 'hex'));
+    receiver.write(Buffer.from('8101318901328a0133820134', 'hex'));
   });
 
   it('does not swallow errors thrown from event handlers', (done) => {
diff --git a/test/websocket.test.js b/test/websocket.test.js
index 5570b1caf..aa53c3bc9 100644
--- a/test/websocket.test.js
+++ b/test/websocket.test.js
@@ -4423,6 +4423,7 @@ describe('WebSocket', () => {
                   'The socket was closed while data was being compressed'
                 );
               });
+              ws.close();
             });
           }
         );