Test coverage is popularly applied in software companies to measure test efforts and create regression test suite. Many service providers actively provide test as a service to software companies to reduce the cost of software test. However, it is a big challenge to store increasing massive test coverage data, such as software build, test traces, etc. In addition, it is also a data-intensive processing for coverage statistics summarization and regression test generation. Hence, data availability and scalability becomes two obstacles for the traditional solutions to be deployed as a service. To overcome these obstacles, in this paper, we propose to leverage the cloud techniques including BigTable and MapReduce to deploy test coverage service.