diff --git a/tests/matlab/CHECK.m b/tests/matlab/CHECK.m
index feb21b896..c4516c3cc 100644
--- a/tests/matlab/CHECK.m
+++ b/tests/matlab/CHECK.m
@@ -1,4 +1,9 @@
 function CHECK(name,assertion)
+% CHECK throw an error if an assertion fails
+%
+% CHECK(name,assertion)
+%  - name of test
+%  - assertion
 
 if (assertion~=1)
   error(['CHECK ' name ' fails']);