accordant-quickref

Accordant Quick Reference

State Definition

[State]
public partial class MyState
{
    public Dictionary<string, decimal> Balances { get; set; } = new();
    public Dictionary<string, UserState> Users { get; set; } = new();
}

[State]
public partial class UserState
{
    public string Name { get; set; } = string.Empty;
    public List<string> Tags { get; set; } = new();
}

Create a Spec

var spec = new Spec<MyState>()
    .WithJsonPrinters();  // Optional: nice logging

Define Operations

Inline Syntax

spec.Operation<TRequest, TResponse>("OperationName", (request, state) =>
{
    // Return ExpectedOutcomes
});

Examples

// Simple request (single value)
spec.Operation<string, ApiResult<User>>("GetUser", (userId, state) => { ... });

// Tuple request (multiple values)
spec.Operation<(string Id, decimal Amount), ApiResult<decimal>>("Deposit", (request, state) =>
{
    var (id, amount) = request;  // Destructure
    // ...
});

// Class-based request
spec.Operation<CreateUserRequest, ApiResult<User>>("CreateUser", (request, state) => { ... });

Expected Outcomes

Basic Expectation

Expect.That<TResponse>(response => /* predicate */)

With Explanation (Recommended)

Expect.That<ApiResult<decimal>>(
    r => r.IsSuccess && r.Data == expectedValue,
    $"Expected success with value {expectedValue}")

With ValidationResult

Expect.That<User>(response =>
{
    if (response.Name != expected)
        return ValidationResult.Invalid($"Name mismatch: {response.Name}");
    return ValidationResult.Valid();
})

Exception Expectation

Expect.Throws<NotFoundException>("Resource not found")

Multiple Valid Outcomes

Expect.OneOf(
    Expect.That<T>(r => /* outcome 1 */).ThenState(...),
    Expect.That<T>(r => /* outcome 2 */).SameState(),
    Expect.That<T>(r => /* outcome 3 */).ThenState(...)
)

State Transitions