Effect-TS Testing Patterns

Comprehensive testing patterns for Effect-TS services, errors, layers, and effects. Use this skill when writing tests for Effect-based code.

Core Testing Setup

@effect/vitest Integration

import { describe, it, expect } from "@effect/vitest"
import { Effect } from "effect"

// Basic test - it.effect provides TestContext automatically
it.effect("test name", () =>
  Effect.gen(function* () {
    const result = yield* someEffect
    expect(result).toBe(expected)
  })
)