fsharp-testing

사용 방법

설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.

npx skills add https://github.com/affaan-m/ecc --skill fsharp-testing

시작 전 확인

설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.

원본 Skill 문서

원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.

F# Testing Patterns

Comprehensive testing patterns for F# applications using xUnit, FsUnit, Unquote, FsCheck, and modern .NET testing practices.

When to Activate

Writing new tests for F# code
Reviewing test quality and coverage
Setting up test infrastructure for F# projects
Debugging flaky or slow tests

Test Framework Stack

Tool	Purpose
xUnit	Test framework (standard .NET ecosystem choice)
FsUnit.xUnit	F#-friendly assertion syntax for xUnit
Unquote	Assertion library using F# quotations for clear failure messages
FsCheck.xUnit	Property-based testing integrated with xUnit
NSubstitute	Mocking .NET dependencies
Testcontainers	Real infrastructure in integration tests
WebApplicationFactory	ASP.NET Core integration tests

Unit Tests with xUnit + FsUnit

Basic Test Structure

fsharp

module OrderServiceTests

open Xunit
open FsUnit.Xunit

[<Fact>]
let ``create sets status to Pending`` () =
    let order = Order.create "cust-1" [ validItem ]
    order.Status |> should equal Pending

[<Fact>]
let ``confirm changes status to Confirmed`` () =
    let order = Order.create "cust-1" [ validItem ]
    let confirmed = Order.confirm order
    confirmed.Status |> should be (ofCase <@ Confirmed @>)

Assertions with Unquote

Unquote uses F# quotations so failure messages show the full expression that failed, not just "expected X got Y".

fsharp

module OrderValidationTests

open Xunit
open Swensen.Unquote

[<Fact>]
let ``PlaceOrder returns success when request is valid`` () =
    let request = { CustomerId = "cust-123"; Items = [ validItem ] }
    let result = OrderService.placeOrder request
    test <@ Result.isOk result @>

[<Fact>]
let ``order total sums item prices`` () =
    let items = [ { Sku = "A"; Quantity = 2; Price = 10m }
                  { Sku = "B"; Quantity = 1; Price = 5m } ]
    let total = Order.calculateTotal items
    test <@ total = 25m @>

[<Fact>]
let ``validated email rejects empty input`` () =
    let result = ValidatedEmail.create ""
    test <@ Result.isError result @>

Async Tests

fsharp

[<Fact>]
let ``PlaceOrder returns success when request is valid`` () = task {
    let deps = createTestDeps ()
    let request = { CustomerId = "cust-123"; Items = [ validItem ] }

    let! result = OrderService.placeOrder deps request

    test <@ Result.isOk result @>
}

[<Fact>]
let ``PlaceOrder returns error when items are empty`` () = task {
    let deps = createTestDeps ()
    let request = { CustomerId = "cust-123"; Items = [] }

    let! result = OrderService.placeOrder deps request

    test <@ Result.isError result @>
}

Parameterized Tests with Theory

fsharp

[<Theory>]
[<InlineData("")>]
[<InlineData("   ")>]
let ``PlaceOrder rejects empty customer ID`` (customerId: string) =
    let request = { CustomerId = customerId; Items = [ validItem ] }
    let result = OrderService.placeOrder request
    result |> should be (ofCase <@ Error @>)

[<Theory>]
[<InlineData("", false)>]
[<InlineData("a", false)>]
[<InlineData("user@example.com", true)>]
[<InlineData("user+tag@example.co.uk", true)>]
let ``IsValidEmail returns expected result`` (email: string, expected: bool) =
    test <@ EmailValidator.isValid email = expected @>

Property-Based Testing with FsCheck

Using FsCheck.xUnit

fsharp

open FsCheck
open FsCheck.Xunit

[<Property>]
let ``order total is always non-negative`` (items: NonEmptyList<PositiveInt * decimal>) =
    let orderItems =
        items.Get
        |> List.map (fun (qty, price) ->
            { Sku = "SKU"; Quantity = qty.Get; Price = abs price })
    let total = Order.calculateTotal orderItems
    total >= 0m

[<Property>]
let ``serialization roundtrips`` (order: Order) =
    let json = JsonSerializer.Serialize order
    let deserialized = JsonSerializer.Deserialize<Order> json
    deserialized = order

Custom Generators

fsharp

type OrderGenerators =
    static member ValidEmail () =
        gen {
            let! user = Gen.elements [ "alice"; "bob"; "carol" ]
            let! domain = Gen.elements [ "example.com"; "test.org" ]
            return $"{user}@{domain}"
        }
        |> Arb.fromGen

[<Property(Arbitrary = [| typeof<OrderGenerators> |])>]
let ``valid emails pass validation`` (email: string) =
    EmailValidator.isValid email

Mocking Dependencies

Function Stubs (Preferred)

fsharp

let createTestDeps () =
    let mutable savedOrders = []
    { FindOrder = fun id -> task { return Map.tryFind id testData }
      SaveOrder = fun order -> task { savedOrders <- order :: savedOrders }
      SendNotification = fun _ -> Task.CompletedTask }

[<Fact>]
let ``PlaceOrder saves the confirmed order`` () = task {
    let mutable saved = []
    let deps =
        { createTestDeps () with
            SaveOrder = fun order -> task { saved <- order :: saved } }

    let! _ = OrderService.placeOrder deps validRequest

    test <@ saved.Length = 1 @>
}

NSubstitute for .NET Interfaces

fsharp

open NSubstitute

[<Fact>]
let ``calls repository with correct ID`` () = task {
    let repo = Substitute.For<IOrderRepository>()
    repo.FindByIdAsync(Arg.Any<Guid>(), Arg.Any<CancellationToken>())
        .Returns(Task.FromResult(Some testOrder))

    let service = OrderService(repo)
    let! _ = service.GetOrder(testOrder.Id, CancellationToken.None)

    do! repo.Received(1).FindByIdAsync(testOrder.Id, Arg.Any<CancellationToken>())
}

ASP.NET Core Integration Tests

fsharp

type OrderApiTests (factory: WebApplicationFactory<Program>) =
    interface IClassFixture<WebApplicationFactory<Program>>

    let client =
        factory.WithWebHostBuilder(fun builder ->
            builder.ConfigureServices(fun services ->
                services.RemoveAll<DbContextOptions<AppDbContext>>() |> ignore
                services.AddDbContext<AppDbContext>(fun options ->
                    options.UseInMemoryDatabase("TestDb") |> ignore) |> ignore))
            .CreateClient()

    [<Fact>]
    member _.``GET order returns 404 when not found`` () = task {
        let! response = client.GetAsync($"/api/orders/{Guid.NewGuid()}")
        test <@ response.StatusCode = HttpStatusCode.NotFound @>
    }

Test Organization

tests/
  MyApp.Tests/
    Unit/
      OrderServiceTests.fs
      PaymentServiceTests.fs
    Integration/
      OrderApiTests.fs
      OrderRepositoryTests.fs
    Properties/
      OrderPropertyTests.fs
    Helpers/
      TestData.fs
      TestDeps.fs

Common Anti-Patterns

Anti-Pattern	Fix
Testing implementation details	Test behavior and outcomes
Mutable shared test state	Fresh state per test
`Thread.Sleep` in async tests	Use `Task.Delay` with timeout, or polling helpers
Asserting on `sprintf` output	Assert on typed values and pattern matches
Ignoring `CancellationToken`	Always pass and verify cancellation
Skipping property-based tests	Use FsCheck for any function with clear invariants

Related Skills

dotnet-patterns - Idiomatic .NET patterns, dependency injection, and architecture
csharp-testing - C# testing patterns (shared infrastructure like WebApplicationFactory and Testcontainers applies to F# too)

Running Tests

bash

# Run all tests
dotnet test

# Run with coverage
dotnet test --collect:"XPlat Code Coverage"

# Run specific project
dotnet test tests/MyApp.Tests/

# Filter by test name
dotnet test --filter "FullyQualifiedName~OrderService"

# Watch mode during development
dotnet watch test --project tests/MyApp.Tests/

사용 방법

시작 전 확인

F# Testing Patterns

When to Activate

Test Framework Stack

Unit Tests with xUnit + FsUnit

Basic Test Structure

Assertions with Unquote

Async Tests

Parameterized Tests with Theory

Property-Based Testing with FsCheck

Using FsCheck.xUnit

Custom Generators

Mocking Dependencies

Function Stubs (Preferred)

NSubstitute for .NET Interfaces

ASP.NET Core Integration Tests

Test Organization

Common Anti-Patterns

Related Skills

Running Tests

관련 작업

더 많은 Skills

scientific-thinking-literature-review

docker-patterns

agentic-engineering

backend-patterns

fsharp-testing

사용 방법

시작 전 확인

F# Testing Patterns

When to Activate

Test Framework Stack

Unit Tests with xUnit + FsUnit

Basic Test Structure

Assertions with Unquote

Async Tests

Parameterized Tests with Theory

Property-Based Testing with FsCheck

Using FsCheck.xUnit

Custom Generators

Mocking Dependencies

Function Stubs (Preferred)

NSubstitute for .NET Interfaces

ASP.NET Core Integration Tests

Test Organization

Common Anti-Patterns

Related Skills

Running Tests

관련 작업

laravel-tdd

tdd-workflow

rea-ci-tests-audit

springboot-security

더 많은 Skills

scientific-thinking-literature-review

docker-patterns

agentic-engineering

backend-patterns