In this paper we describe a comprehensive approach for conformance testing of embedded reactive systems. Based on a formal specification, namely UML state machines, we automatically generate test cases and use them to check the functional conformance of a system under test. Our test cases include not only stimuli to trigger the system under test, they also include possible correct observations to automatically evaluate the test case execution. In contrast to classical Harel Statecharts, state machines behave asynchronously, which makes automatic test case generation a challenge. The TEAGER Tool Suite implements the automatic generation, execution and evaluation of test cases and proves the applicability of our test approach.