In this work, we face the problem of generating good quality test suites and test cases for web services. We present a framework to test web services based on their formal description, following a black-box approach and using Property-Based Testing.Web services are a popular solution to integrate components when building a software system, or to allow communication between a system and third-party users, providing a flexible, reusable mechanism to access its functionalities. Testing of web services is a key activity: we need to verify their behaviour and ensure their quality as much as possible, as efficiently as possible.By automatically deriving QuickCheck models from its WSDL description and its OCL semantic constraints, we enable generation and execution of great amounts of automatically generated test cases. Thus, we avoid the usual compromise between effort and cost, which too often leads to smaller and less exhaustive test suites than desirable.To illustrate the advantages of our framework, we present an industrial case study: a distributed system which serves media contents customers' TV screens.