Functional Programming tools in Golang that use Go 1.18 Generics
General Purpose tools for Functional Programming
- Generic set operations on Golang arrays: Filtering, Union, Intersection, Minus
- Generic Linked List
- Generic function composition
- Generic sort
- Generic function currying and partial application
Type-Checked Properties-based testing that is based upon ScalaCheck and Haskell Quickcheck
- Everything has strong typing thanks to Golang Generics.
- Many kinds of test data generators
- Every generator is composable. Lots of generators are included already and new ones are easy to make as compositions of existing generators.
- A property is composable with other properties
- Assertions are composable with And and Or logic
- Test Failures include the specific generated values that caused test failure as well as the last successful case.
- Programmers can better cover the scope of all possible inputs to a test (i.e. zero values, empty things, etc).
- Tests outcomes are reproducible
- Programmers can eliminate a lot of code duplication and get better tests at the same time because properties-based testing uses random test data.
- Properties-based testing is useful for all sorts of tests: unit, integration, course-grained functional/system/black-box.
A few properties-based testing library exist in Golang. Gopter is an example. This library has much less code than Gopter and provides a very important feature that Gopter does not, namely that all abstractions are fully composable.
Two Key Abstractions
- Generators – Generators are functions that produce random test data.
- They are composable. You can combine them to make other generators.
- They obey algebraic laws. You can guarantee the safety of their compositions.
- They are pure functions, freely shareable between Go Routines.
- Generators allow you to reproduce the exact same test data by passing in the same integer seed value into a SimpleRNG. You should never need to save files of test data again.
- Properties – Properties are functions that execute a predicate-like function over a set of test data generated using a given Generator.
- They are composable – You can combine them in arbitrary ways to make new properties.
- They obey algebraic laws so that you can guarantee the safety of their compositions.
- They are pure functions, freely shareable between Go Routines.
- A property is a function that takes two function arguments:
- one transforming a generated value into a potentially different type
- and one evaluating the preceding value for correctness.
- These two characteristics are a very important feature for test reuse.
Initializing Project
go1.18rc1 mod init pkggo1.18rc1 mod tidygo1.18rc1 test -v -count=1 ./...
