Establish formal lines of communication between the two groups early in the project. Forward any e-mail from you receive from one group to the other if appropriate. Create opportunities for the two groups to interact in an informal setting. Although these tactics may not directly create more testable software, they will allow each team to better understand the other team's problems and challenges. This in itself should encourage the creation of more testable software.
Testers can do many things to make their own jobs easier.
Testers should learn as much as they can about the design of the product they are testing, and the technologies involved. This will help them make informed decisions about what and how to test. Without in-depth knowledge of both the product and the technologies involved, testers could waste a lot valuable testing time on tasks that are unnecessary or performed incorrectly. Insist on testing in a debug environment. The testing environment should be set up to mirror the development environment.