Property-based testing is the process of selecting test data from user-specified properties fro testing a program. Current automatic property-based testing techniques adopt direct
approaches for this task, consisting in generating first test data and then checking whether a property is satisfied or not. are generated at random and rejected when they do not satisfy selected coverage criteria. In this paper, we propose a technique and tool called FocalTest, which adopt a
approach through the usage of constraint reasoning. Our technique utilizes the property to prune the search space during the test data generation process. A particular difficulty is the generation of test data satisfying MC/DC on the precondition of a property, when it contains function calls with pattern matching and high-order functions. Our experimental results show that a non-naive implementation of constraint reasoning on these constructions outperform traditional generation techniques when used to find test data for testing properties.