test-error-helpers.c: In function ‘test_error_helpers_connection_error’:
test-error-helpers.c:36:39: error: comparison of integer expressions of different signedness: ‘guint’ {aka ‘unsigned int’} and ‘gint’ {aka ‘int’} [-Werror=sign-compare]
36 | for (i = enum_class->minimum; i <= enum_class->maximum; i++) { \
| ^~
Defining the new error codes in the headers is not enough, we also
need to add support in the error helpers in order to create proper
GErrors with the expected error codes.