This report details the development and testing of a GUI application in C# using Visual Studio, as part of the INFO815 Software Development and Testing course. The project involves comparing terms from two user-selected folders containing documents, displaying terms in a textbox with five terms per line, and implementing a doubly linked list for data storage, adhering to the assignment's restriction against built-in data structures. The report includes a critical analysis of the development methodology, emphasizing the use of DLLs for data handling and Microsoft.Office.Interop.Word for document processing. Unit testing, including white-box testing, is thoroughly covered, with explanations of test cases for boundary scenarios and complex methods, alongside the use of the Test Explorer in Visual Studio. The report presents code snippets, screenshots, and video demonstrations to illustrate the implementation and testing procedures, including considerations for the application's design, comments, and indentation, and includes discussion of the DLL methods and unit testing in C#.