1. A computer system for testing an extract, transform, load job (ETL job), the computer system comprising: one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage medium, and program instructions stored on at least one of the one or more tangible storage medium for execution by at least one of the one or more processors via at least one of the one or more memories, wherein the computer system is capable of performing a method comprising: receiving, by a processor, an uploaded ETL job; executing a functionality test of the uploaded ETL job using a test bucket; determining the executed functionality test produces a failure result; creating at least one test sub-job corresponding to at least one stage within on the uploaded ETL job; generating a plurality of test data for each of the at least one created test sub-job; executing the at least one created test sub-job using the plurality of generated test data; and creating a report based on a plurality of results associated with the at least one executed test sub-job.