Line number mappings across target commits

In this study, every pair of commits that introduce and remove a test smell instance needs to be obtained for studying how long each smell instance exists in its codebase. However, the tool for detecting test smells can only produce smell detection results on one commit per run. Between two target commits, the outputs of an unchanged smell instance could be different as changes could happen in other parts of the code. Thus, this item is for mapping the tool's output across different commits. This item contains information extracted from the "git diff" command which is used for mapping line numbers of a smell instance between two target commits.