Add a test of invalid values to bad_client

test/core/bad_client/tests/initial_settings_frame.c

@@ -35,6 +35,7 @@
 #include "src/core/surface/server.h"
 
 #define PFX_STR "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
+#define ONE_SETTING_HDR "\x00\x00\x06\x04\x00\x00\x00\x00\x00"
 
 static void verifier(grpc_server *server, grpc_completion_queue *cq) {
   while (grpc_server_has_open_connections(server)) {
@@ -90,6 +91,10 @@ int main(int argc, char **argv) {
                            PFX_STR "\x00\x00\x04\x04\x00\x00\x00\x00\x00", 0);
   GRPC_RUN_BAD_CLIENT_TEST(verifier,
                            PFX_STR "\x00\x00\x05\x04\x00\x00\x00\x00\x00", 0);
+  /* some settings values are illegal */
+  /* max frame size = 0 */
+  GRPC_RUN_BAD_CLIENT_TEST(verifier,
+                           PFX_STR ONE_SETTING_HDR "\x00\x05\x00\x00\x00\x00", GRPC_BAD_CLIENT_DISCONNECT);
 
   return 0;
 }