hrynco-common/HrynCo.Common.Tests/HealthChecksTests.cs

namespace HrynCo.Common.Tests;

using HrynCo.Common.HealthChecks;
using HrynCo.Common.HealthChecks.Defaults;
using HrynCo.Common.HealthChecks.Interfaces;
using FluentAssertions;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Xunit;

public sealed class HealthChecksTests
{
    [Fact]
    public async Task CompositeHealthCheck_ShouldUseConfigurationCheckWhenConfiguredForConfigOnly()
    {
        var configCheck = new FakeConfigurationCheck();
        var serviceCheck = new FakeServiceHealthCheck();
        var healthCheck = new CompositeHealthCheck(configCheck, serviceCheck, configOnly: true);

        HealthCheckResult result = await healthCheck.CheckHealthAsync(new HealthCheckContext(), default);

        result.Status.Should().Be(HealthStatus.Healthy);
        configCheck.Called.Should().BeTrue();
        serviceCheck.Called.Should().BeFalse();
    }

    [Fact]
    public async Task CompositeHealthCheck_ShouldUseServiceCheckWhenNotConfigOnly()
    {
        var configCheck = new FakeConfigurationCheck();
        var serviceCheck = new FakeServiceHealthCheck();
        var healthCheck = new CompositeHealthCheck(configCheck, serviceCheck, configOnly: false);

        HealthCheckResult result = await healthCheck.CheckHealthAsync(new HealthCheckContext(), default);

        result.Status.Should().Be(HealthStatus.Healthy);
        configCheck.Called.Should().BeFalse();
        serviceCheck.Called.Should().BeTrue();
    }

    [Fact]
    public async Task DbServiceHealthCheck_ShouldReturnHealthyWhenConnectionSucceeds()
    {
        var check = new DbServiceHealthCheck(new FakeDatabaseConnectionChecker(true));

        HealthCheckResult result = await check.CheckHealthAsync(default);

        result.Status.Should().Be(HealthStatus.Healthy);
    }

    [Fact]
    public async Task DbServiceHealthCheck_ShouldReturnUnhealthyWhenConnectionFails()
    {
        var check = new DbServiceHealthCheck(new FakeDatabaseConnectionChecker(false));

        HealthCheckResult result = await check.CheckHealthAsync(default);

        result.Status.Should().Be(HealthStatus.Unhealthy);
    }

    private sealed class FakeConfigurationCheck : IConfigurationCheck
    {
        public bool Called { get; private set; }

        public Task<HealthCheckResult> CheckConfigurationAsync(CancellationToken cancellationToken)
        {
            _ = cancellationToken;
            Called = true;
            return Task.FromResult(HealthCheckResult.Healthy("config"));
        }
    }

    private sealed class FakeServiceHealthCheck : IServiceHealthCheck
    {
        public bool Called { get; private set; }

        public Task<HealthCheckResult> CheckHealthAsync(CancellationToken cancellationToken)
        {
            _ = cancellationToken;
            Called = true;
            return Task.FromResult(HealthCheckResult.Healthy("service"));
        }
    }

    private sealed class FakeDatabaseConnectionChecker : IDatabaseConnectionChecker
    {
        private readonly bool _canConnect;

        public FakeDatabaseConnectionChecker(bool canConnect)
        {
            _canConnect = canConnect;
        }

        public Task<bool> CanConnectAsync(CancellationToken cancellationToken)
        {
            _ = cancellationToken;
            return Task.FromResult(_canConnect);
        }
    }
}