diff --git a/tests/utils.c b/tests/utils.c
index b9d1d6b50..9d8a95cda 100644
--- a/tests/utils.c
+++ b/tests/utils.c
@@ -48,6 +48,7 @@ int test_memio_write_cb(WOLFSSL *ssl, char *data, int sz, void *ctx)
     int *len;
     int *msg_sizes;
     int *msg_count;
+    int *forceWantWrite;
 
     test_ctx = (struct test_memio_ctx*)ctx;
 
@@ -56,14 +57,19 @@ int test_memio_write_cb(WOLFSSL *ssl, char *data, int sz, void *ctx)
         len = &test_ctx->c_len;
         msg_sizes = test_ctx->c_msg_sizes;
         msg_count = &test_ctx->c_msg_count;
+        forceWantWrite = &test_ctx->c_force_want_write;
     }
     else {
         buf = test_ctx->s_buff;
         len = &test_ctx->s_len;
         msg_sizes = test_ctx->s_msg_sizes;
         msg_count = &test_ctx->s_msg_count;
+        forceWantWrite = &test_ctx->s_force_want_write;
     }
 
+    if (*forceWantWrite)
+        return WOLFSSL_CBIO_ERR_WANT_WRITE;
+
     if ((unsigned)(*len + sz) > TEST_MEMIO_BUF_SZ)
         return WOLFSSL_CBIO_ERR_WANT_WRITE;
 
@@ -362,16 +368,30 @@ int test_memio_setup_ex(struct test_memio_ctx *ctx,
     return 0;
 }
 
+void test_memio_simulate_want_write(struct test_memio_ctx *ctx, int is_client,
+        int enable)
+{
+    if (ctx == NULL)
+        return;
+
+    if (is_client)
+        ctx->c_force_want_write = (enable != 0);
+    else
+        ctx->s_force_want_write = (enable != 0);
+}
+
 void test_memio_clear_buffer(struct test_memio_ctx *ctx, int is_client)
 {
     if (is_client) {
         ctx->c_len = 0;
         ctx->c_msg_pos = 0;
         ctx->c_msg_count = 0;
+        ctx->c_force_want_write = 0;
     } else {
         ctx->s_len = 0;
         ctx->s_msg_pos = 0;
         ctx->s_msg_count = 0;
+        ctx->s_force_want_write = 0;
     }
 }
 
diff --git a/tests/utils.h b/tests/utils.h
index 31d56caa4..aa5c2d436 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -44,6 +44,9 @@ struct test_memio_ctx
     int s_len;
     const char* s_ciphers;
 
+    int c_force_want_write;
+    int s_force_want_write;
+
     int c_msg_sizes[TEST_MEMIO_MAX_MSGS];
     int c_msg_count;
     int c_msg_pos;
@@ -64,6 +67,8 @@ int test_memio_setup_ex(struct test_memio_ctx *ctx,
     method_provider method_c, method_provider method_s,
     byte *caCert, int caCertSz, byte *serverCert, int serverCertSz,
     byte *serverKey, int serverKeySz);
+void test_memio_simulate_want_write(struct test_memio_ctx *ctx, int is_client,
+        int enable);
 void test_memio_clear_buffer(struct test_memio_ctx *ctx, int is_client);
 int test_memio_inject_message(struct test_memio_ctx *ctx, int client, const char *data, int sz);
 int test_memio_copy_message(const struct test_memio_ctx *ctx, int client,