Erlang QuickCheck Tutorial

Thomas Arts

Testing is a major part of all software development - yet no matter how
much effort is spent on it, some errors always seem to slip through.
Cases which no-one thought to test crash systems late in development or
out in the field, revealing errors which cost time and money to analyze,
diagnose, and fix. In the worst case, such errors reveal fundamental
flaws which force a redesign of part of the system, at disproportionate
cost.

QuickCheck is an automated testing tool, originating from research by
John Hughes and Koen Claessen and commercialized by Quviq. QuickCheck
addresses the testing challenges by generating test cases from a concise
specification (so that many more cases can be tested), and simplifying
failing cases to a minimal example on a test failure (so that fault
diagnosis is quick and easy). QuickCheck enables developers to generate
tests from specifications. It enables them to find errors at an earlier
stage, lowering costs and improving quality as a result.

In this tutorial, Thomas Arts will use examples to show how developers 
write QuickCheck specifications - which are actually Erlang programs
using the QuickCheck API - and use them to test code written in Erlang
or other programming languages. We will see how QuickCheck's shrinking
finds tiny examples that provoke errors, making the step from observing
a bug to diagnosing it very short indeed, and we will show how property
driven development can produce code that is solid from the word go.

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Dr. Thomas Arts is the co-founder and CTO of Quviq, a small company that 
produced QuickCheck, a testing tool for Erlang. Thomas has one foot in 
academia as associate professor at the IT University of Gothenburg and 
one foot in industry. He has over 30 research publications and he has 
successfully introduced some new technologies to the industry, the 
latest being QuickCheck, a tool for property based testing and aims to 
support test driven development. Thomas has formerly been employed at 
the Ericsson Computer Science Lab (where they invented Erlang), where he 
worked on program verification and the development of the Erlang 
programming language. He has worked in the broad spectrum theoretical 
computer science, formal methods and industrial case-study research, 
mainly applying all kind of techniques to systems written in Erlang.