README.md

Rapid

Rapid is a Go library for property-based testing.

Rapid checks that properties you define hold for a large number of automatically generated test cases. If a failure is found, rapid automatically minimizes the failing test case before presenting it.

Property-based testing emphasizes thinking about high level properties the program should satisfy rather than coming up with a list of individual examples of desired behavior (test cases). This results in concise and powerful tests that are a pleasure to write.

Design and implementation of rapid are heavily inspired by Hypothesis, which is itself a descendant of QuickCheck.

Features

• Idiomatic Go API
  • Designed to be used together with go test and the testing package
  • Works great with libraries like testify/require and testify/assert
• Automatic minimization of failing test cases
• No dependencies outside of the Go standard library

Planned features

• Automatic persistence of failing test cases

Examples

Example function and state machine tests are provided. They both fail. Making them pass is a good way to get first real experience of working with rapid.

Comparison

Rapid aims to bring to Go the power and convenience Hypothesis brings to Python.

Compared to gopter, rapid:

• has a much simpler API (queue test in rapid vs gopter)
• does not require any user code to minimize failing test cases
• uses more sophisticated algorithms for data generation

Compared to testing/quick, rapid:

• provides much more control over test case generation
• supports state machine ("stateful" or "model-based") testing
• automatically minimizes any failing test case
• has to settle for rapid.Check being the main exported function instead of much more stylish quick.Check

Status

Rapid is alpha software. Important pieces of functionality are missing; API breakage and bugs should be expected.

If rapid fails to find a bug you believe it should, or the failing test case that rapid reports does not look like a minimal one, please open an issue.

License

Rapid is licensed under the Mozilla Public License version 2.0.