Roles in Agile Team
In an Agile team, are two roles defined "customer team" and "developer team". The difference between them is basically the skills of each team.
The Customer team writes the stories that the developer team delivers. The testers are members of the
customer team, helping the customer express their requirements as tests.
This team also include business experts, product owners, everyone on the "business" side of a project.
The Developer team is everyone involved with delivering code. The programmers, architect, database administrators, system administrators are part of the team.Testers are also on the developer team because testing is a central component of agile software developement.
The Customer and Developer teams, work together with a commomn goal. They work to define requirements with test and examples and write the code that makes the test pass.
Testers understand the customer viewpoint as well as the complexities of the technical implementation. Some agile teams, don't have "testers" members but the experience with Agile teams has shown that testing skills and experience are vital to project success and the testers adds value to agile team.