Unittests

Implement a first set of unittest for Fortran using FortUTF framework. C/C++ test are implemented in googletests.

src/mo_exception.f90

@@ -130,7 +130,13 @@ MODULE mo_exception
 
     id = proc_id
     nerr = nerr_unit
-    lwrite = l_write_output .OR. l_extra_output
+
+    IF (PRESENT(l_extra_output)) THEN
+      lwrite = l_write_output .OR. l_extra_output
+    ELSE 
+      lwrite = l_write_output
+    ENDIF
+
     model_abort => callback_abort
 
     IF (PRESENT(callback_traceback)) THEN