Exercise Testing Tracing

AFP Exercise 4: Testing and Tracing

For the fourth exercise of AFP, you have to use the Quickcheck library as well as the Hat debugging tools. More precisely, you are asked to answer the questions about merge-sort that are included in the Quickcheck/Hat paper. These questions can be found in Section 7.1 on pages 37 and 38 (Exercises 1-7).

In addition to your answers for the seven questions, please give a short opinion (5-10 sentences) about the usefulness of Quickcheck and Hat for testing and tracing functional programs. How well did you get on with the tools? Will you ever consider using it for larger applications?

Resources

• The paper Testing and Tracing Lazy Functional Programs using QuickCheck and Hat
  (Claessen, Runciman, Chitil, Hughes, Wallace) containing the exercises.

• The example programs are available at http://www.cs.york.ac.uk/fp/afp02/. Alternatively, you may also use this zip file.

• Quickcheck is part of GHC's hierarchical libraries, and the latest version can be found here.

• The sources for building Hat can be found at the project's homepage (check out the system requirements first). You need to install hmake beforehand.

General remark

Building the hat-trail and hat-observe tools for Linux or Mac OS should be relatively easy. However, to get it running on the Windows platform is said to be more complicated. If someone succeeds in building these tools for Windows, please put the executables online so that others can benefit from your efforts.