exp_expression_with_stack: added check for null pointer after obtaining a mutex in test

components/esp_common/include/esp_expression_with_stack.h

@@ -29,7 +29,7 @@
  */
 #define ESP_EXECUTE_EXPRESSION_WITH_STACK(lock, stack, stack_size, expression)  \
 ({                                                                  \
-    if(lock && stack && stack_size) {                               \
+    if (lock && stack && stack_size) {                              \
         uint32_t backup;                                            \
         xSemaphoreTake(lock, portMAX_DELAY);                        \
         StackType_t *top_of_stack = esp_switch_stack_setup(stack, stack_size);\

components/newlib/test/test_shared_stack_printf.c

@@ -22,6 +22,8 @@ TEST_CASE("test printf using shared buffer stack", "[newlib]")
     TEST_ASSERT(shared_stack != NULL);
 
     SemaphoreHandle_t printf_lock = xSemaphoreCreateMutex();
+    TEST_ASSERT_NOT_NULL(printf_lock);
+
     ESP_EXECUTE_EXPRESSION_WITH_STACK(printf_lock, shared_stack,8192,printf("Executing this printf from external stack! \n"));
     ESP_EXECUTE_EXPRESSION_WITH_STACK(printf_lock, shared_stack,8192,another_external_stack_function()); 
     vSemaphoreDelete(printf_lock);