A DBUnit developer works with the DBUnit testing framework to manage database-driven projects. They create and maintain databases, write code to interact with these databases, and ensure data integrity. They also develop and implement testing strategies to verify the functionality and performance of database systems. This involves creating test data, running tests, and analyzing the results for any issues. Their role is crucial in identifying and resolving problems that could impact the performance, security, and reliability of the application. They also collaborate with other team members and stakeholders, providing technical expertise on database-related matters.