request/src/Request.Tests/ScalarBehaviourTests.cs

// Copyright (c) The Geekeey Authors
// SPDX-License-Identifier: EUPL-1.2

using Microsoft.Extensions.DependencyInjection;

namespace Geekeey.Request.Tests;

internal sealed class ScalarBehaviourTests
{
	[Test]
	public async Task I_can_execute_the_closed_behaviour()
	{
		var sc = new ServiceCollection();
		sc.AddSingleton<ScalarTestTracker>();
		sc.AddRequestDispatcher(builder => builder
			.Add(typeof(ScalarTestHandler))
			.Add(typeof(ScalarTestBehavior)));
		var provider = sc.BuildServiceProvider();
		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
		var tracker = provider.GetRequiredService<ScalarTestTracker>();

		var request = new ScalarTestRequest { Value = "Hello" };
		var result = await dispatcher.DispatchAsync(request);

		await Assert.That(result).IsEquivalentTo("Hello-Handled");
		await Assert.That(tracker.Executed).IsTrue();
	}

	[Test]
	public async Task I_can_execute_the_open_behaviour()
	{
		var sc = new ServiceCollection();
		sc.AddSingleton<ScalarTestTracker>();
		sc.AddRequestDispatcher(builder => builder
			.Add(typeof(ScalarTestHandler))
			.Add(typeof(ScalarOpenBehavior<,>)));
		var provider = sc.BuildServiceProvider();
		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
		var tracker = provider.GetRequiredService<ScalarTestTracker>();

		var request = new ScalarTestRequest { Value = "Hello" };
		var result = await dispatcher.DispatchAsync(request);

		await Assert.That(result).IsEquivalentTo("Hello-Handled");
		await Assert.That(tracker.Executed).IsTrue();
	}

	[Test]
	public async Task I_can_chain_the_behaviours_in_order()
	{
		var sc = new ServiceCollection();
		sc.AddSingleton<ScalarTestTracker>();
		sc.AddRequestDispatcher(builder => builder
			.Add(typeof(ScalarTestHandler))
			.Add(typeof(ScalarChainedBehaviour1))
			.Add(typeof(ScalarChainedBehaviour2)));
		var provider = sc.BuildServiceProvider();
		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
		var tracker = provider.GetRequiredService<ScalarTestTracker>();

		var request = new ScalarTestRequest { Value = "Hello" };
		await dispatcher.DispatchAsync(request);

		// They are discovered in the order they appear in the assembly.
		// In this file: ChainedBehaviour1, ChainedBehaviour2
		await Assert.That(tracker.Log).Count().IsEqualTo(2);
		await Assert.That(tracker.Log[0]).IsEquivalentTo("Behaviour1");
		await Assert.That(tracker.Log[1]).IsEquivalentTo("Behaviour2");
	}

	[Test]
	public async Task I_can_work_with_a_generic_wrapper_request_and_the_open_behaviour()
	{
		var sc = new ServiceCollection();
		sc.AddSingleton<ScalarTestTracker>();
		sc.AddRequestDispatcher(builder => builder
			.Add(typeof(ScalarTestWrapperHandler<>))
			.Add(typeof(ScalarWrapperBehavior<>)));
		var provider = sc.BuildServiceProvider();
		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
		var tracker = provider.GetRequiredService<ScalarTestTracker>();

		var request = new ScalarTestWrapperRequest<int> { Item = 42 };
		var result = await dispatcher.DispatchAsync(request);

		await Assert.That(result).IsEquivalentTo("Handled-42");
		await Assert.That(tracker.Executed).IsTrue();
	}

	[Test]
	public async Task I_can_maintain_the_ordering_between_open_and_closed_behaviours()
	{
		var sc = new ServiceCollection();
		sc.AddSingleton<ScalarTestTracker>();
		sc.AddRequestDispatcher(builder => builder
			.Add(typeof(ScalarTestHandler))
			.Add(typeof(ScalarOrderingOpenBehavior<,>))
			.Add(typeof(ScalarOrderingClosedBehavior)));
		var provider = sc.BuildServiceProvider();
		var dispatcher = provider.GetRequiredService<IRequestDispatcher>();
		var tracker = provider.GetRequiredService<ScalarTestTracker>();

		var request = new ScalarTestRequest { Value = "Order" };
		await dispatcher.DispatchAsync(request);

		await Assert.That(tracker.Log).Contains("OrderingOpen");
		await Assert.That(tracker.Log).Contains("OrderingClosed");
	}
}

public class ScalarTestTracker
{
	public List<string> Log { get; } = [];
	public bool Executed { get; set; }
}

public class ScalarOrderingOpenBehavior<TRequest, TOutput>(ScalarTestTracker tracker) : IScalarRequestBehavior<TRequest, TOutput>
	where TRequest : IScalarRequest<TOutput>
{
	public Task<TOutput> HandleAsync(TRequest request, ScalarHandlerDelegate<TOutput> next, CancellationToken cancellationToken)
	{
		tracker.Log.Add("OrderingOpen");
		return next(request, cancellationToken);
	}
}

public class ScalarOrderingClosedBehavior(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
{
	public Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
	{
		tracker.Log.Add("OrderingClosed");
		return next(request, cancellationToken);
	}
}

public class ScalarTestRequest : IScalarRequest<string>
{
	public string Value { get; set; } = string.Empty;
}

public class ScalarTestHandler : IScalarRequestHandler<ScalarTestRequest, string>
{
	public Task<string> HandleAsync(ScalarTestRequest request, CancellationToken cancellationToken)
	{
		return Task.FromResult($"{request.Value}-Handled");
	}
}

public class ScalarTestBehavior(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
{
	public async Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
	{
		tracker.Executed = true;
		return await next(request, cancellationToken);
	}
}

public class ScalarOpenBehavior<TRequest, TResponse>(ScalarTestTracker tracker) : IScalarRequestBehavior<TRequest, TResponse>
	where TRequest : IScalarRequest<TResponse>
{
	public async Task<TResponse> HandleAsync(TRequest request, ScalarHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
	{
		tracker.Executed = true;
		return await next(request, cancellationToken);
	}
}

public class ScalarChainedBehaviour1(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
{
	public async Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
	{
		tracker.Log.Add("Behaviour1");
		return await next(request, cancellationToken);
	}
}

public class ScalarChainedBehaviour2(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestRequest, string>
{
	public async Task<string> HandleAsync(ScalarTestRequest request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
	{
		tracker.Log.Add("Behaviour2");
		return await next(request, cancellationToken);
	}
}

public class ScalarTestWrapperRequest<T> : IScalarRequest<string>
{
	public T Item { get; set; } = default!;
}

public class ScalarTestWrapperHandler<T> : IScalarRequestHandler<ScalarTestWrapperRequest<T>, string>
{
	public Task<string> HandleAsync(ScalarTestWrapperRequest<T> request, CancellationToken cancellationToken)
	{
		return Task.FromResult($"Handled-{request.Item}");
	}
}

public class ScalarWrapperBehavior<T>(ScalarTestTracker tracker) : IScalarRequestBehavior<ScalarTestWrapperRequest<T>, string>
{
	public async Task<string> HandleAsync(ScalarTestWrapperRequest<T> request, ScalarHandlerDelegate<string> next, CancellationToken cancellationToken)
	{
		tracker.Executed = true;
		return await next(request, cancellationToken);
	}
}