Fault-based conformance testing is a conformance testing strategy that relies on specific fault models. Previously, this mutation testing technique has been applied to protocol specifications. Although a practical case study of web-server testing has been conducted, we observed several issues when applying this method in a large industrial project. In this paper, we discuss the foundations, techniques and tools to overcome these shortcomings. More specifically, we show a solution to the problem

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... of state-space explosion in generating mutation tests for industrial scale applications. Furthermore, the previous approach used the counterexamples of a bisimulation check (between the original and the mutant) as test purposes. With respect to input-output conformance (ioco), this is an over-approximation resulting in more tests than are necessary. Hence, we propose to use an ioco-checker in order to generate less test cases. An industrial case study demonstrates these improvements.