diff -r 8990ac138cc2 -r 7c263b864371 tests/misc.py
--- a/tests/misc.py	Mon Jan 22 21:04:53 2018 +0200
+++ b/tests/misc.py	Mon Jan 22 21:21:53 2018 +0200
@@ -1,6 +1,7 @@
 from testsuite import warning
 
 def colours_test(model):
+    ''' Checks that all colours used in the part model are valid. '''
     yield from (
         warning(element, 'bad-colour', colour_index = element.colour.index)
         for element in model.body