Testing

ExUnit ships with Elixir — async tests, doctests, setup callbacks, and rich assertions out of the box. ExMachina creates test factories. Mox enables concurrent, explicit mocks based on behaviours. Bypass stubs external HTTP calls. Wallaby drives browser tests. StreamData provides property-based testing. The testing story in Elixir is first-class from day one.

ExUnit

Need a test framework?

Built-in test framework with async test support, doctests, setup callbacks, and rich assertions

Replaces: RSpec pytest Jest Mocha

ExMachina

Need test data factories?

Test factory library for creating Ecto structs and maps with associations

Replaces: FactoryBot Faker factory_boy

Mox

Need mocking for tests?

Library for defining concurrent, explicit mocks based on behaviours

Replaces: Mockery unittest.mock Jest mocks

Mimic

Need mocking without behaviours?

Flexible mocking library combining the best of Mox and Meck with stubs, expectations, and call tracking

Bypass

Need to mock external API calls?

Stub external HTTP requests by creating a custom plug server on a local port

Replaces: VCR WebMock nock

Wallaby

Need end-to-end browser testing?

Browser-based integration testing with concurrent sessions and automatic screenshots

Replaces: Capybara Cypress Playwright

StreamData

Need to test with random inputs?

Property-based testing and data generation for finding edge cases automatically

Replaces: QuickCheck Hypothesis fast-check

Companion Project

Postgres Is Enough

Simplify your database layer too. A curated directory of PostgreSQL extensions and tools that replace Redis, Elasticsearch, Kafka, and more.