BMUnit is the package which integrates Byteman into JUnit and TestNG, enabling you to locally redefine the behaviour of application or JDK runtime code for the duration of a single test or group of related tests. BMUnit is very simple to use; just add a few annotations to your test classes and place a few jars in your classpath. This talk will explain how BMUnit works by presenting and executing tests which exemplify the 3 most common use cases:

• injecting trace code so you can be sure your tests enter the expected code paths

• injecting validation rules so you can assert that specific outcomes do occur

• injecting 'faults' to modify state or control flow, driving the application or JDK runtime down the path needed to exercise a desired test scenario

(Please note that this talk replaces 'Displaying Application Events in Thermostat Using Byteman')