diff --git a/README.md b/README.md
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@@ -22,7 +22,7 @@ This project is being developed at Masaryk University, Brno, as collaborative pr
 * The source code has to be maintainable via Maven. If you use IDEA for development, be carefull that this IDE transforms the original Maven project into its own obscure format. You can use it, but at the end, your code has to be installable and runnable via maven (see Installation and running). When pushing your code into gitlab, the maven installation is tested.
 * Document public interafaces rigorously.
 * Commit and push regularly. Keet branches (iterations) as short as possible.
-* Write junit test whenever possible.
+* Write junit test whenever possible. For the `MesmModel` module, unit tests are mandatory for every new functionality! 
 * The client part (GUI) of the project is developed in [NetBeans Platform](https://netbeans.apache.org/kb/docs/platform/index.html) framework.
 
 ## Structure (modules):