effect-testing

Name: effect-testing
Availability: InStock
Author: twlines

Demonstrate Effect-TS testing patterns with Vitest for deterministic unit tests.

Updated Feb 5, 2026

Search Tags:#typescript #vitest #testing #effect-ts #mocking #layer

Ready to run

npx skills add https://github.com/twlines/maslow --skill effect-testing-twlines

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: effect-testing
Source: https://github.com/twlines/maslow/tree/main/skills/effect-testing
Command: npx skills add https://github.com/twlines/maslow --skill effect-testing-twlines

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill provides clear, actionable patterns and best practices for writing effective tests for Effect-TS applications, ensuring robust and maintainable code.

Core Features & Use Cases

Mocking Services: Demonstrates how to effectively mock dependencies using Layer.succeed.
Layer Composition: Shows how to compose multiple layers for comprehensive test environments.
Error Testing: Illustrates how to test for expected error conditions.
Use Case: When developing a new feature using Effect-TS, you can consult this Skill to quickly implement reliable unit tests that accurately reflect the behavior of your services and handle potential errors gracefully.

Quick Start

Use the effect-testing skill to learn how to mock services with Layer.succeed.

Frequently Asked Questions about effect-testing

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I mock services in Effect-TS using Vitest?▼

To mock services in Effect-TS using Vitest, you can use the `Layer.succeed` method to create deterministic test layers that replace real dependencies with fixed implementations for unit testing.

What is the best way to compose multiple test layers in Effect-TS?▼

Composing multiple test layers in Effect-TS involves combining individual mocked layers to build a comprehensive test environment, ensuring your unit tests accurately reflect service behaviors and handle errors gracefully.

How does Vitest work with Effect-TS for testing expected errors?▼

Vitest works with Effect-TS by allowing you to test for expected error conditions within a deterministic environment, verifying that your Effect-TS services handle potential errors gracefully during execution.

Does Effect-TS testing with Vitest have a specific timeout constraint?▼

Effect-TS testing patterns with Vitest adhere to rules for fast, reliable tests within a 10-second timeout, ensuring that your unit tests execute quickly and deterministically without hanging.

When do I need to use Layer.succeed for Effect-TS unit tests?▼

You need to use `Layer.succeed` for Effect-TS unit tests when you want to mock service dependencies, allowing you to isolate the service under test and ensure reliable, deterministic results.