# Module junit-jupiter-migrationsupport This module provides support for JUnit 4 rules within JUnit Jupiter. Currently, this support is limited to subclasses of the ```org.junit.rules.Verifier``` and ```org.junit.rules.ExternalResource``` rules of JUnit 4, respectively. Please note that a general support for arbitrary ```org.junit.rules.TestRule``` implementations is not possible within the JUnit Jupiter extension model. The main purpose of this module is to facilitate the migration of large JUnit 4 codebases containing such JUnit 4 rules by minimizing the effort needed to run such legacy tests under JUnit 5. By using one of the two provided class-level extensions on a test class such rules in legacy code bases can be left unchanged including the JUnit 4 rule import statements. However, if you intend to develop a *new* extension for JUnit 5 please use the new extension model of JUnit Jupiter instead of the rule-based model of JUnit 4.