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

namespace HrynCo.Common.Tests;

using System.Collections.Concurrent;
using HrynCo.Common;
using FluentAssertions;
using Serilog;
using Serilog.Core;
using Serilog.Events;
using Xunit;

public sealed class ProfilerTests
{
    [Fact]
    public async Task MeasureExecutionAsync_ShouldReturnResultAndWriteStartAndEndEvents()
    {
        var sink = new CollectingSink();
        ILogger logger = new LoggerConfiguration()
            .MinimumLevel.Verbose()
            .WriteTo.Sink(sink)
            .CreateLogger();

        var profiler = new Profiler(logger);

        int result = await profiler.MeasureExecutionAsync(async () =>
        {
            await Task.Delay(1);
            return 42;
        }, "LoadItems");

        result.Should().Be(42);
        sink.Events.Count.Should().BeGreaterThan(1);
        sink.Events.Should().ContainSingle(e =>
            e.Level == LogEventLevel.Information
            && e.MessageTemplate.Text.Contains("Start", StringComparison.Ordinal)
            && e.Properties["BlockName"].ToString().Contains("LoadItems", StringComparison.Ordinal));
        sink.Events.Should().ContainSingle(e =>
            e.Level == LogEventLevel.Information
            && e.MessageTemplate.Text.Contains("End", StringComparison.Ordinal)
            && e.Properties["Measurements"].ToString().Contains("True", StringComparison.Ordinal));
    }

    [Fact]
    public async Task MeasureExecutionAsync_ActionOverload_ShouldInvokeAction()
    {
        var sink = new CollectingSink();
        ILogger logger = new LoggerConfiguration()
            .MinimumLevel.Verbose()
            .WriteTo.Sink(sink)
            .CreateLogger();

        var profiler = new Profiler(logger);
        bool invoked = false;

        await profiler.MeasureExecutionAsync(async () =>
        {
            invoked = true;
            await Task.CompletedTask;
        }, "ActionBlock");

        invoked.Should().BeTrue();
    }

    [Fact]
    public async Task MeasureExecutionAsync_ShouldLogErrorAndRethrow()
    {
        var sink = new CollectingSink();
        ILogger logger = new LoggerConfiguration()
            .MinimumLevel.Verbose()
            .WriteTo.Sink(sink)
            .CreateLogger();

        var profiler = new Profiler(logger);

        Func<Task> act = async () =>
        {
            await profiler.MeasureExecutionAsync<int>(() => throw new InvalidOperationException("boom"), "FailBlock");
        };

        await act.Should().ThrowAsync<InvalidOperationException>();
        sink.Events.Should().Contain(e =>
            e.Level == LogEventLevel.Error
            && e.MessageTemplate.Text.Contains("An error occurred", StringComparison.Ordinal));
    }

    private sealed class CollectingSink : ILogEventSink
    {
        public ConcurrentQueue<LogEvent> Events { get; } = new();

        public void Emit(LogEvent logEvent)
        {
            Events.Enqueue(logEvent);
        }
    }
}