fengling-gateway/tests/YarpGateway.Tests/Unit/Services/RouteCacheTests.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Moq;
using Xunit;
using FluentAssertions;
using YarpGateway.Data;
using YarpGateway.Models;
using YarpGateway.Services;

namespace YarpGateway.Tests.Unit.Services;

public class RouteCacheTests
{
    private readonly Mock<IDbContextFactory<GatewayDbContext>> _dbContextFactoryMock;
    private readonly Mock<ILogger<RouteCache>> _loggerMock;

    public RouteCacheTests()
    {
        _dbContextFactoryMock = new Mock<IDbContextFactory<GatewayDbContext>>();
        _loggerMock = new Mock<ILogger<RouteCache>>();
    }

    private GatewayDbContext CreateInMemoryDbContext(List<GwTenantRoute> routes)
    {
        var options = new DbContextOptionsBuilder<GatewayDbContext>()
            .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString())
            .Options;

        var context = new GatewayDbContext(options);
        context.TenantRoutes.AddRange(routes);
        context.SaveChanges();
        
        return context;
    }

    private RouteCache CreateRouteCache(GatewayDbContext context)
    {
        _dbContextFactoryMock
            .Setup(x => x.CreateDbContext())
            .Returns(context);

        return new RouteCache(
            dbContextFactory: _dbContextFactoryMock.Object,
            logger: _loggerMock.Object
        );
    }

    [Fact]
    public async Task InitializeAsync_ShouldLoadGlobalRoutes()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "user-service",
                ClusterId = "cluster-user",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            },
            new GwTenantRoute
            {
                Id = 2,
                TenantCode = "",
                ServiceName = "order-service",
                ClusterId = "cluster-order",
                PathPattern = "/api/order/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);

        // Act
        await routeCache.InitializeAsync();

        // Assert
        var result = routeCache.GetRoute("any-tenant", "user-service");
        result.Should().NotBeNull();
        result!.ClusterId.Should().Be("cluster-user");
    }

    [Fact]
    public async Task InitializeAsync_ShouldLoadTenantRoutes()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "tenant-1",
                ServiceName = "user-service",
                ClusterId = "cluster-tenant-user",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = false,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);

        // Act
        await routeCache.InitializeAsync();

        // Assert
        var result = routeCache.GetRoute("tenant-1", "user-service");
        result.Should().NotBeNull();
        result!.ClusterId.Should().Be("cluster-tenant-user");
    }

    [Fact]
    public async Task GetRoute_WithTenantRouteAvailable_ShouldReturnTenantRoute()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "tenant-1",
                ServiceName = "user-service",
                ClusterId = "tenant-cluster",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = false,
                IsDeleted = false
            },
            new GwTenantRoute
            {
                Id = 2,
                TenantCode = "",
                ServiceName = "user-service",
                ClusterId = "global-cluster",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act
        var result = routeCache.GetRoute("tenant-1", "user-service");

        // Assert - tenant route should be prioritized
        result.Should().NotBeNull();
        result!.ClusterId.Should().Be("tenant-cluster");
    }

    [Fact]
    public async Task GetRoute_WithoutTenantRoute_ShouldFallbackToGlobal()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "user-service",
                ClusterId = "global-cluster",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act
        var result = routeCache.GetRoute("unknown-tenant", "user-service");

        // Assert
        result.Should().NotBeNull();
        result!.ClusterId.Should().Be("global-cluster");
    }

    [Fact]
    public async Task GetRoute_WithMissingRoute_ShouldReturnNull()
    {
        // Arrange
        var routes = new List<GwTenantRoute>();
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act
        var result = routeCache.GetRoute("tenant-1", "non-existent");

        // Assert
        result.Should().BeNull();
    }

    [Fact]
    public async Task GetRouteByPath_WithValidPath_ShouldReturnRoute()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "user-service",
                ClusterId = "cluster-user",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act
        var result = routeCache.GetRouteByPath("/api/user/users");

        // Assert
        result.Should().NotBeNull();
        result!.ClusterId.Should().Be("cluster-user");
    }

    [Fact]
    public async Task GetRouteByPath_WithMissingPath_ShouldReturnNull()
    {
        // Arrange
        var routes = new List<GwTenantRoute>();
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act
        var result = routeCache.GetRouteByPath("/unknown/path");

        // Assert
        result.Should().BeNull();
    }

    [Fact]
    public async Task ReloadAsync_ShouldClearOldRoutes()
    {
        // Arrange
        var initialRoutes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "old-service",
                ClusterId = "old-cluster",
                PathPattern = "/api/old/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(initialRoutes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Verify initial state
        routeCache.GetRoute("any", "old-service").Should().NotBeNull();

        // Modify the database (replace routes)
        context.TenantRoutes.RemoveRange(context.TenantRoutes);
        context.TenantRoutes.Add(new GwTenantRoute
        {
            Id = 2,
            TenantCode = "",
            ServiceName = "new-service",
            ClusterId = "new-cluster",
            PathPattern = "/api/new/**",
            Priority = 1,
            Status = 1,
            IsGlobal = true,
            IsDeleted = false
        });
        context.SaveChanges();

        // Act
        await routeCache.ReloadAsync();

        // Assert - old route should be gone, new route should exist
        routeCache.GetRoute("any", "old-service").Should().BeNull();
        routeCache.GetRoute("any", "new-service").Should().NotBeNull();
    }

    [Fact]
    public async Task InitializeAsync_ShouldExcludeDeletedRoutes()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "active-service",
                ClusterId = "cluster-1",
                PathPattern = "/api/active/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            },
            new GwTenantRoute
            {
                Id = 2,
                TenantCode = "",
                ServiceName = "deleted-service",
                ClusterId = "cluster-2",
                PathPattern = "/api/deleted/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = true
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Assert
        routeCache.GetRoute("any", "active-service").Should().NotBeNull();
        routeCache.GetRoute("any", "deleted-service").Should().BeNull();
    }

    [Fact]
    public async Task InitializeAsync_ShouldExcludeInactiveRoutes()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "active-service",
                ClusterId = "cluster-1",
                PathPattern = "/api/active/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            },
            new GwTenantRoute
            {
                Id = 2,
                TenantCode = "",
                ServiceName = "inactive-service",
                ClusterId = "cluster-2",
                PathPattern = "/api/inactive/**",
                Priority = 1,
                Status = 0, // Inactive
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Assert
        routeCache.GetRoute("any", "active-service").Should().NotBeNull();
        routeCache.GetRoute("any", "inactive-service").Should().BeNull();
    }

    [Fact]
    public async Task GetRoute_ConcurrentReads_ShouldBeThreadSafe()
    {
        // Arrange
        var routes = new List<GwTenantRoute>
        {
            new GwTenantRoute
            {
                Id = 1,
                TenantCode = "",
                ServiceName = "user-service",
                ClusterId = "cluster-user",
                PathPattern = "/api/user/**",
                Priority = 1,
                Status = 1,
                IsGlobal = true,
                IsDeleted = false
            }
        };
        
        var context = CreateInMemoryDbContext(routes);
        var routeCache = CreateRouteCache(context);
        await routeCache.InitializeAsync();

        // Act & Assert - multiple concurrent reads should not throw
        var tasks = Enumerable.Range(0, 100)
            .Select(_ => Task.Run(() => routeCache.GetRoute("any", "user-service")))
            .ToList();

        var results = await Task.WhenAll(tasks);

        // All results should be consistent
        results.Should().AllSatisfy(r => r.Should().NotBeNull());
    }
}