One or more computers is configured to run an end-to-end test including at least a plurality of independent tests of multiple stages of an asynchronous multi-stage data processing system. One of the set of independent tests is configured to send a request for test input data from a test data repository service for a particular stage. A converted version of the test input data is obtained. A comparison of the converted version to the output of the particular stage to verify operation of the particular stage is obtained. The output of the particular stage is transmitted to the test data repository service. One or more computers is configured to provide the test data repository service. The test data repository service is configured to store in the test data storage the output of the particular stage as test input data for a next stage of the asynchronous multi-stage data processing system.