Though software testing courses are commonly taught as part of software engineering curricula, software testing is still a challenging issue in software engineering education. Students frequently see testing only as something that happens at the end of the development process. Two challenges can be recognized: "how to make the students recognize the relevance of the testing activity?" and "how to motivate the students on using testing ideas in their projects?". In an attempt to explore the impact of introducing testing practices throughout development, during the past Fall semester we modified the project requirements in a course on object-oriented analysis and design offered to the undergraduate students in computer science at Georgia Institute of Technology. Our idea was to require the students to start thinking about testing as early as possible, by including testing-related practices in all phases of the development process. This paper presents the details of the testing approach used in the course and discusses the results we obtained, in terms of the students' attitudes and learning.