effect-testing-mocking

• You need deterministic tests without external IO
• You want to inject mock services via layers

```ts

const RepoTest = Layer.succeed(Repo, Repo.of({ find: () => Effect.succeed(mock) }))

```

```ts

const result = yield* Effect.provide(program, RepoTest)

```

```ts

// Provide a deterministic Clock or use platform TestClock layer if available

```

• Keep tests focused and fast; avoid network by mocking services
• Provide layers explicitly to match program requirements
• Keep tests close to real interfaces; do not reshape app code for tests
• Use .Default layers for quick wiring; add custom mock layers per test
• Favor small smoke tests that run quickly and fail fast

• Leaking real IO into tests → flakiness
• Over-mocking internals → brittle tests; mock at service boundary

• Layers & Services for DI patterns
• Time/Logging for deterministic time and observable output

CRITICAL: Search local Effect source before implementing

The full Effect source code is available at docs/effect-source/. Always search the actual implementation before writing Effect code.

Key Source Files

• Layer: docs/effect-source/effect/src/Layer.ts
• TestClock: docs/effect-source/effect/src/TestClock.ts
• TestContext: docs/effect-source/effect/src/TestContext.ts

Example Searches

```bash

# Find Layer.succeed patterns for mocks

grep -F "Layer.succeed" docs/effect-source/effect/src/Layer.ts

# Study TestClock operations

grep -F "TestClock" docs/effect-source/effect/src/TestClock.ts

# Find test helpers

grep -F "TestContext" docs/effect-source/effect/src/TestContext.ts

# Look at Layer test examples

grep -F "Layer.succeed" docs/effect-source/effect/test/Layer.test.ts

```

Workflow

1. Identify the testing API you need (e.g., Layer.succeed, TestClock)
2. Search docs/effect-source/effect/src/Layer.ts for the implementation
3. Study the types and testing patterns
4. Look at test files for usage examples
5. Write your code based on real implementations

Real source code > documentation > assumptions

```ts

export const TestLayer = (input?: TestLiveInput) =>

Effect.gen(function* () {

const tempDir = tempy.temporaryDirectory({ prefix: 'test' })

const cwd = (yield* setupFixtureFolder({ fixture: input?.fixture, tempDir })) ?? tempDir

const NodeOsTest = Layer.succeed(NodeOs, new NodeOs({ homedir: cwd, arch: 'arm64', platform: 'darwin' }))

const NodeProcessTest = Layer.succeed(NodeProcess, new NodeProcess({ cwd, platform: 'darwin', arch: 'arm64' }))

const ToolkitsRepoTest = Layer.succeed(ComposioToolkitsRepository, new ComposioToolkitsRepository({

getToolkits: () => Effect.succeed([]),

getToolsAsEnums: () => Effect.succeed([])

}))

const layers = Layer.mergeAll(

Console.setConsole(yield* MockConsole.effect),

CliConfig.layer(ComposioCliConfig),

NodeProcessTest,

Layer.provideMerge(ComposioUserContextLive, Layer.merge(BunFileSystem.layer, NodeOsTest)),

ToolkitsRepoTest,

EnvLangDetector.Default,

JsPackageManagerDetector.Default,

BunFileSystem.layer,

BunContext.layer,

MockTerminal.layer,

BunPath.layer

)

return layers

}).pipe(

Logger.withMinimumLogLevel(LogLevel.Debug),

Effect.scoped,

Layer.unwrapEffect,

Layer.provide(Layer.setConfigProvider(input?.baseConfigProvider ?? ConfigProvider.fromMap(new Map([]))))

)

```

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