Abstract. Model Driven Engineering (MDE) advocates the use of models and transformations to support all the tasks of software development, from analysis to testing and maintenance. Modern MDE methodologies employ multiple models, to represent the different perspectives of the system at a progressive level of abstraction. In these situations, MDE frameworks need to work on a set of interdependent models and tranformations, which may evolve over time. This paper presents a model transformation framework capable of aligning two streams of transformations: the forward engineering stream that goes from the Computation Independent Model to the running code, and the testing stream that goes from the Computation Independent Test specification to an executable test script. The "vertical" transformations composing the two streams are kept aligned, by means of "horizontal" mappings that can be applied after a change in the modeling framework (e.g., an update in the PIM-to-code transformation due to a change in the target deployment technology). The proposed framework has been implemented and is under evaluation in a real-world MDE tool.