Software testing is one of the verification and validation activities of software development process. Test automation is relevant, since manual application of tests is laborious and more prone to error. The choice of test tools should be based on criteria and evidence of their usefulness and ease of use. This paper presents an acceptance empirical assessment of open source testing tools. Practitioners and graduate students evaluated five tools often used in the industry. The results describe how these tools are perceived in terms of ease of use and usefulness. These results can support software practitioners in the process of choosing testing tools for their projects.