In the field of search based software testing, genetic algorithm based testing has received a major share of attention among researchers during the last few years. Though there are advantages for this type of testing, there also exist some practical difficulties which can make this technique less attractive for software testing industry. The potential of program slicing in testing has not been fully exploited till now and the works that have explicitly demonstrated the application of slicing in testing field are rare. Our paper aims to analyze existing techniques for software testing and to introduce an approach for software testing using program slicing technique. A systematic review of genetic algorithm based works reveals that, fitness function design, population initialization and parameter settings impact the quality of solution obtained in software testing using genetic algorithm. Based on the conclusions from the existing literature, we have probed deeper about the issues in these areas. Making an unbiased review like this may help to solve these unresolved issues in genetic algorithm based software testing. In this work, we have emphasized and has given clear directions on how slicing can be used as a potential tool for practical software testing. In addition, a set of research questions have been framed, which may be answered by reviewing the study made in this work. This may help future research in this area, leading to major breakthrough in software testing field.