Refactoring Steps, Java Refactorings and Empirical Evidence

While we can determine the likely testing effort of a single refactoring through simple visual inspection, the inter-relationships between many of the seventy- two refactorings mean that a chain of refactorings and hence a chain of tests may be required for completion of each. In this paper, we establish the properties of, and the inter-relationships between, fourteen of the seventy-two refactorings described in Fowler from a testing chain perspective. We provide an empirical analysis of those refactorings and their associated testing chains. We also inform our understanding of testing effort with recourse to refactoring data from 7 Java OSS.