1. A computer program product embodied on a non-transitory computer readable medium, comprising: detecting, by a system, a change made to a particular portion of software, wherein prior to the change the software was determined to be stable; determining, by the system from at least one repository, one or more functional testing entities mapped to the portion of software, each functional testing entity of the one or more functional testing entities providing functional scenario test coverage for the software; determining, by the system from the at least one repository, one or more additional portions of the software mapped to the determined one or more functional testing entities, the one or more additional portions of the software being determined to be potentially impacted by the change made to the particular portion of the software by virtue of the one or more additional portions of the software and the particular portion of the software having a common mapping to the one or more functional testing entities; determining, by the system, an impact score for each of the determined one or more functional testing entities, wherein the impact score indicates an impact of the functional testing entity on regression testing of the software and is based at least on a criticality predefined for the functional testing entity; determining, by the system from the at least one repository, testing rules and test cases mapped to the determined one or more functional testing entities; generating, by the system according to the impact scores for the determined one or more functional testing entities, a graph showing the determined one or more functional testing entities; prioritizing, by the system, the one or more functional testing entities based on the graph; and performing, by the system according to the prioritization, regression testing on the one or more additional portions of the software determined to be mapped to the determined one or more functional testing entities, using the testing rules and test cases determined to be mapped to the determined one or more functional testing entities.