Testing and benchmarking
The libraries in this subsection are as follows:
QuickCheck: Property-checking with automatic test-case generation
doctest: Writing tests and expected results directly in haddock comments
HSpec, HUnit, tasty: Traditional unit-testing libraries
criterion: Benchmarking time usage
weigh: Benchmark allocation
There are two testing libraries that are rather novel in Haskell: QuickCheck and doctest. QuickCheck lets the programmer just state a property for a function, leaving it to the library to try proving it false.
Doctest builds on the ingenious idea of combining test cases with docstrings. It's especially useful in libraries, because it gives users reading the documentation always up-to-date information about properties and use of functions that have tests annotated in their documentation.
More traditional testing frameworks such as HSpec, HUnit, tasty and time-benchmarking library criterion are discussed in detail in Chapter 4, The Devil's in the Detail.
A newcomer library...
