diff -r f0a6bf48b05e -r 8949af6a4279 testsuite.py
--- a/testsuite.py	Sat Jun 08 01:32:25 2019 +0300
+++ b/testsuite.py	Sat Jun 08 01:42:48 2019 +0300
@@ -17,6 +17,17 @@
             bad_object = bad_object,
             **args,
         )
+    def placeholder_message(self):
+        if callable(self.message):
+            import inspect
+            spec = inspect.getfullargspec(self.message)
+            args = {}
+            assert not spec.varargs and not spec.varkw
+            for argname in spec.args + spec.kwonlyargs:
+                args[argname] = '<' + argname.replace('_', ' ') + '>'
+            return self.message(**args)
+        else:
+            return self.message
 
 class Problem:
     def __init__(self, problem_class, bad_object, **args):
@@ -160,9 +171,16 @@
         messages.append(message)
     return '\n'.join(messages)
 
-def all_warning_types(test_suite):
+def iterate_problems(test_suite):
     for test_function in test_suite['tests']:
         yield from test_function.ldcheck_problem_types.values()
+    
+def all_problem_types(test_suite):
+    return sorted(
+        iterate_problems(test_suite),
+        key = lambda problem_type: problem_type.name
+    )
+    
 
 if __name__ == '__main__':
     from pprint import pprint