KArtSell.Aegis/tests/KArtSell.Integration.Tests/KisConnectionPoolTests.cs

using Dapper;
using KArtSell.Host.Infrastructure;
using Npgsql;
using Xunit;

namespace KArtSell.Integration.Tests;

[Collection("Database")]
public class KisConnectionPoolTests : IAsyncLifetime
{
    private readonly NpgsqlDataSource _dataSource;
    private readonly KisConnectionPool _pool;

    public KisConnectionPoolTests(DatabaseFixture fixture)
    {
        _dataSource = fixture.DataSource;
        _pool = new KisConnectionPool(_dataSource, new HttpClient(), fixture.Logger<KisConnectionPool>());
    }

    public async Task InitializeAsync()
    {
        await using var conn = await _dataSource.OpenConnectionAsync();
        await conn.ExecuteAsync("""
            CREATE SCHEMA IF NOT EXISTS kis;
            CREATE TABLE IF NOT EXISTS kis.connection_pool_state (
                id BIGSERIAL PRIMARY KEY,
                connection_id UUID NOT NULL UNIQUE,
                state VARCHAR(50) NOT NULL,
                priority INT NOT NULL,
                token_hash VARCHAR(256),
                expires_at TIMESTAMP WITH TIME ZONE,
                created_at TIMESTAMP WITH TIME ZONE NOT NULL,
                released_at TIMESTAMP WITH TIME ZONE,
                published_at TIMESTAMP WITH TIME ZONE NOT NULL
            );
            CREATE TABLE IF NOT EXISTS kis.token_refresh_log (
                id BIGSERIAL PRIMARY KEY,
                connection_id UUID NOT NULL,
                refresh_at TIMESTAMP WITH TIME ZONE NOT NULL,
                status VARCHAR(50) NOT NULL,
                error_message TEXT,
                new_token_hash VARCHAR(256),
                executed_at TIMESTAMP WITH TIME ZONE NOT NULL,
                published_at TIMESTAMP WITH TIME ZONE NOT NULL
            );
            TRUNCATE kis.connection_pool_state CASCADE;
            TRUNCATE kis.token_refresh_log CASCADE;
            """);
    }

    public async Task DisposeAsync()
    {
        await _pool.DisposeAsync();
    }

    [Fact]
    public async Task AcquireAsync_CreatesConnection_WhenPoolEmpty()
    {
        // Act
        var conn = await _pool.AcquireAsync();

        // Assert
        Assert.NotEqual(Guid.Empty, conn.ConnectionId);
        Assert.Equal("active", conn.State);
    }

    [Fact]
    public async Task AcquireAsync_MaintainsPoolSize_Between3And5()
    {
        // Act - Create 5 connections
        var connections = new List<KisConnection>();
        for (int i = 0; i < 5; i++)
        {
            connections.Add(await _pool.AcquireAsync());
        }

        // Assert - Verify count in database
        await using var dbConn = await _dataSource.OpenConnectionAsync();
        var count = await dbConn.QueryFirstOrDefaultAsync<int>(
            "SELECT COUNT(*) FROM kis.connection_pool_state WHERE state IN ('active', 'idle')");

        Assert.True(count <= 5, $"Pool size exceeded: {count}");
    }

    [Fact]
    public async Task ReleaseAsync_ReturnsConnectionToPool_Idempotent()
    {
        // Arrange
        var conn = await _pool.AcquireAsync();
        var connId = conn.ConnectionId;

        // Act - Release and re-acquire
        await _pool.ReleaseAsync(connId);
        var reused = await _pool.AcquireAsync();

        // Assert - Should reuse released connection
        Assert.Equal(connId, reused.ConnectionId);
    }
}