5 files changed, 6 insertions, 10 deletions
diff --git a/test/cpp/interop/http2_client.cc b/test/cpp/interop/http2_client.cc
index 1e04e57d09..2de7abcf17 100644
--- a/test/cpp/interop/http2_client.cc
+++ b/test/cpp/interop/http2_client.cc
@@ -217,7 +217,7 @@ int main(int argc, char** argv) {
         "goaway",         "max_streams",      "ping",
         "rst_after_data", "rst_after_header", "rst_during_data"};
     char* joined_testcases =
-        gpr_strjoin_sep(testcases, GPR_ARRAY_SIZE(testcases), "\n", NULL);
+        gpr_strjoin_sep(testcases, GPR_ARRAY_SIZE(testcases), "\n", nullptr);
 
     gpr_log(GPR_ERROR, "Unsupported test case %s. Valid options are\n%s",
             FLAGS_test_case.c_str(), joined_testcases);
diff --git a/test/cpp/interop/interop_server.cc b/test/cpp/interop/interop_server.cc
index 7a028111ef..30bd8bfef8 100644
--- a/test/cpp/interop/interop_server.cc
+++ b/test/cpp/interop/interop_server.cc
@@ -51,8 +51,9 @@ using grpc::ServerCredentials;
 using grpc::ServerReader;
 using grpc::ServerReaderWriter;
 using grpc::ServerWriter;
-using grpc::WriteOptions;
 using grpc::SslServerCredentialsOptions;
+using grpc::Status;
+using grpc::WriteOptions;
 using grpc::testing::InteropServerContextInspector;
 using grpc::testing::Payload;
 using grpc::testing::SimpleRequest;
@@ -62,7 +63,6 @@ using grpc::testing::StreamingInputCallResponse;
 using grpc::testing::StreamingOutputCallRequest;
 using grpc::testing::StreamingOutputCallResponse;
 using grpc::testing::TestService;
-using grpc::Status;
 
 const char kEchoInitialMetadataKey[] = "x-grpc-test-echo-initial";
 const char kEchoTrailingBinMetadataKey[] = "x-grpc-test-echo-trailing-bin";
diff --git a/test/cpp/interop/interop_test.cc b/test/cpp/interop/interop_test.cc
index c18fe1ec1f..1bf0d8d10f 100644
--- a/test/cpp/interop/interop_test.cc
+++ b/test/cpp/interop/interop_test.cc
@@ -37,10 +37,8 @@
 #include "test/core/util/port.h"
 #include "test/cpp/util/test_config.h"
 
-extern "C" {
 #include "src/core/lib/iomgr/socket_utils_posix.h"
 #include "src/core/lib/support/string.h"
-}
 
 DEFINE_string(extra_server_flags, "", "Extra flags to pass to server.");
 
diff --git a/test/cpp/interop/reconnect_interop_server.cc b/test/cpp/interop/reconnect_interop_server.cc
index 50af8fcc8a..5e257e1b38 100644
--- a/test/cpp/interop/reconnect_interop_server.cc
+++ b/test/cpp/interop/reconnect_interop_server.cc
@@ -53,9 +53,9 @@ using grpc::ServerWriter;
 using grpc::SslServerCredentialsOptions;
 using grpc::Status;
 using grpc::testing::Empty;
-using grpc::testing::ReconnectService;
 using grpc::testing::ReconnectInfo;
 using grpc::testing::ReconnectParams;
+using grpc::testing::ReconnectService;
 
 static bool got_sigint = false;
 
diff --git a/test/cpp/interop/stress_test.cc b/test/cpp/interop/stress_test.cc
index c6d3600be8..4b39dc3211 100644
--- a/test/cpp/interop/stress_test.cc
+++ b/test/cpp/interop/stress_test.cc
@@ -36,9 +36,7 @@
 #include "test/cpp/util/metrics_server.h"
 #include "test/cpp/util/test_config.h"
 
-extern "C" {
 extern void gpr_default_log(gpr_log_func_args* args);
-}
 
 DEFINE_int32(metrics_port, 8081, "The metrics server port.");
 
@@ -106,13 +104,13 @@ DEFINE_bool(use_test_ca, false, "False to use SSL roots for google");
 DEFINE_string(server_host_override, "foo.test.google.fr",
               "Override the server host which is sent in HTTP header");
 
-using grpc::testing::kTestCaseList;
 using grpc::testing::MetricsService;
 using grpc::testing::MetricsServiceImpl;
 using grpc::testing::StressTestInteropClient;
 using grpc::testing::TestCaseType;
 using grpc::testing::UNKNOWN_TEST;
 using grpc::testing::WeightedRandomTestSelector;
+using grpc::testing::kTestCaseList;
 
 static int log_level = GPR_LOG_SEVERITY_DEBUG;
 
@@ -230,7 +228,7 @@ int main(int argc, char** argv) {
   log_level = FLAGS_log_level;
   gpr_set_log_function(TestLogFunction);
 
-  srand(time(NULL));
+  srand(time(nullptr));
 
   // Parse the server addresses
   std::vector<grpc::string> server_addresses;