diff --git a/test/mock/mock_att_server.c b/test/mock/mock_att_server.c
index d06910741..55209af5f 100644
--- a/test/mock/mock_att_server.c
+++ b/test/mock/mock_att_server.c
@@ -16,11 +16,18 @@
 #include "CppUTestExt/MockSupport.h"
 
 static att_service_handler_t * service;
+static btstack_context_callback_registration_t * mock_callback_registration;
 
 att_service_handler_t * mock_att_server_get_service(void){
     return service;
 }
 
+void mock_deinit(void){
+    mock().clear();
+    mock_callback_registration = NULL;
+    service = NULL;
+}
+
 uint16_t mock_att_service_read_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
     btstack_assert(service != NULL);
     btstack_assert(service->read_callback != NULL);
@@ -37,6 +44,11 @@ void att_server_register_service_handler(att_service_handler_t * handler){
     service = handler;
 }
 
+void mock_att_service_trigger_can_send_now(void){
+    btstack_assert(mock_callback_registration != NULL);
+    (*mock_callback_registration->callback)(mock_callback_registration->context);
+}
+
 uint16_t att_server_get_mtu(hci_con_handle_t con_handle){
     UNUSED(con_handle);
     mock().actualCall("att_server_get_mtu");
@@ -64,6 +76,8 @@ int att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, co
 int att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
     UNUSED(callback_registration);
     UNUSED(con_handle);
+    mock_callback_registration = callback_registration;
+
     mock().actualCall("att_server_register_can_send_now_callback");
     return ERROR_CODE_SUCCESS;
 }
diff --git a/test/mock/mock_att_server.h b/test/mock/mock_att_server.h
index eb7b54c92..30bd3257b 100644
--- a/test/mock/mock_att_server.h
+++ b/test/mock/mock_att_server.h
@@ -51,6 +51,10 @@ uint16_t mock_att_service_read_callback(hci_con_handle_t con_handle, uint16_t at
 
 uint16_t mock_att_service_write_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t transaction_mode, uint16_t offset, const uint8_t *buffer, uint16_t buffer_size);
 
+void mock_att_service_trigger_can_send_now(void);
+
+void mock_deinit(void);
+
 #if defined __cplusplus
 }
 #endif