[Context:] The choice of testing technique to be adopted in a software testing project persists based on the tester's knowledge and often does not consider all of the testing techniques available in the industry or academia. Therefore, a characterization scheme was proposed and implemented in the SeleCTT tool, which is composed of a set of attributes that considers characteristics of concurrent programs, and they are used to calculate which of these attributes are suitable to guide the selection of testing techniques for a particular software project. [Objective:] The selection of the testing technique at each stage of a software's life cycle depends on many factors. Our work aims to help testers to select a better testing technique according to the characteristics of a software project, contributing to the selection of the most suitable testing technique to increase the efficiency of the software test execution process, which in turn influences the development and delivery of a more robust and quality product. Considering that the testing techniques are complementary, another goal is to allow a set of testing techniques to be selected and not just one. [Methodology:] To achieve this goal, a systematic mapping study was conducted to identify and analyze papers that represent the current state of the literature about testing techniques selection. We surveyed software testing practices carried in Brazil software companies and identified the testing practices to know and have an overview on the latest testing techniques, tools, and metrics used, the challenges faced by testers, and the selection testing technique process. [Results and Conclusions:] With this study, it is expected to specify project attributes that can be used to improve the existing recommendation system in the SeleCTT tool and propose ways of combining testing techniques, contributing to industry and academia, and bring insights into the context of testing techniques selection.