diff --git a/examples/pubsub/publisher_test.cc b/examples/pubsub/publisher_test.cc
index 40b122bc7469c0e05f1bed342f23d140baf6112b..b7bea5b1bd25e12da37f65a10a85f0a71cc07c13 100644
--- a/examples/pubsub/publisher_test.cc
+++ b/examples/pubsub/publisher_test.cc
@@ -138,7 +138,7 @@ TEST_F(PublisherTest, TestPublisher) {
 
   std::vector<grpc::string> topics;
   EXPECT_TRUE(publisher_->ListTopics(kProjectId, &topics).IsOk());
-  EXPECT_EQ(topics.size(), 1);
+  EXPECT_EQ(topics.size(), static_cast<size_t>(1));
   EXPECT_EQ(topics[0], kTopic);
 }