# csharp-test

> Testing standards for C# 14 / .NET 10 with xUnit and Shouldly. Covers naming conventions (Should_X_When_Y), AAA pattern, test data builders, and mocking rules. Use for writing tests, "/test", or "help with tests".

- Author: Zada Zorg
- Repository: zadazorg/csharp-standards
- Version: 20260124224759
- Stars: 0
- Forks: 0
- Last Updated: 2026-02-06
- Source: https://github.com/zadazorg/csharp-standards
- Web: https://mule.run/skillshub/@@zadazorg/csharp-standards~csharp-test:20260124224759

---

---
name: csharp-test
description: >
  Testing standards for C# 14 / .NET 10 with xUnit and Shouldly.
  Covers naming conventions (Should_X_When_Y), AAA pattern, test data builders,
  and mocking rules. Use for writing tests, "/test", or "help with tests".
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metadata:
  author: csharp-standards
  version: "4.0.0"
---

# Testing Standards

Write tests that are **readable, maintainable, and reliable**.

## Core Principles

| Principle | Rule |
|-----------|------|
| Framework | xUnit + Shouldly (NOT FluentAssertions - license!) |
| Naming | `Should_[Result]_When_[Condition]` |
| Structure | AAA: Arrange → Act → Assert |
| SUT | Name object under test `sut` |
| Mocking | Mock ONLY I/O (HTTP, DB, Files) |

## Quick Rules

1. **NO logic in tests** — zero `if`, `for`, `while`
2. **ONE act per test** — single method call
3. **NO `Thread.Sleep`** — use `TimeProvider`
4. **NO mocking records/structs** — use real instances
5. **FluentAssertions FORBIDDEN** — use Shouldly

## Test Structure Template

```csharp
public sealed class OrderServiceTests {
    [Fact]
    public async Task Should_CreateOrder_When_ValidInput() {
        // Arrange
        var repository = Substitute.For<IOrderRepository>();
        var sut = new OrderService(repository);
        var command = new CreateOrderCommand(CustomerId.New(), Money.FromDecimal(99.99m));

        // Act
        var result = await sut.CreateAsync(command, CancellationToken.None);

        // Assert
        result.IsError.ShouldBeFalse();
        result.Value.Id.ShouldNotBe(OrderId.Empty);
    }
}
```

## Testing Internal Types

Add to main project `.csproj`:

```xml
<ItemGroup>
  <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
    <_Parameter1>MyProduct.Tests</_Parameter1>
  </AssemblyAttribute>
</ItemGroup>
```

## Code Coverage

```bash
dotnet test --collect:"XPlat Code Coverage"
```

Required package in test project:
```xml
<PackageReference Include="coverlet.collector" />
```

## References

Load detailed documentation as needed:

| Topic | File |
|-------|------|
| Full Testing Guide | [references/testing.md](references/testing.md) |