// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Text.Encodings.Web;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing.Constraints;
using Microsoft.AspNetCore.Routing.TestObjects;
using Microsoft.AspNetCore.InternalTesting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.WebEncoders.Testing;
using Moq;

namespace Microsoft.AspNetCore.Routing;

public class RouteTest
{
    private static readonly RequestDelegate NullHandler = (c) => Task.CompletedTask;
    private static readonly IInlineConstraintResolver _inlineConstraintResolver = GetInlineConstraintResolver();

    [Fact]
    public void CreateTemplate_InlineConstraint_Regex_Malformed()
    {
        // Arrange
        var template = @"{controller}/{action}/ {p1:regex(abc} ";
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);

        var exception = Assert.Throws<RouteCreationException>(
            () => new Route(
                mockTarget.Object,
                template,
                defaults: null,
                constraints: null,
                dataTokens: null,
                inlineConstraintResolver: _inlineConstraintResolver));

        var expected = "An error occurred while creating the route with name '' and template" +
            $" '{template}'.";
        Assert.Equal(expected, exception.Message);

        Assert.NotNull(exception.InnerException);
        expected = "The constraint entry 'p1' - 'regex(abc' on the route " +
            "'{controller}/{action}/ {p1:regex(abc} ' could not be resolved by the constraint resolver of type " +
            $"'{nameof(DefaultInlineConstraintResolver)}'.";
        Assert.Equal(expected, exception.InnerException.Message);
    }

    [Fact]
    public async Task RouteAsync_MergesExistingRouteData_IfRouteMatches()
    {
        // Arrange
        var template = "{controller}/{action}/{id:int}";

        var context = CreateRouteContext("/Home/Index/5");

        var originalRouteDataValues = context.RouteData.Values;
        originalRouteDataValues.Add("country", "USA");

        var originalDataTokens = context.RouteData.DataTokens;
        originalDataTokens.Add("company", "Contoso");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: null,
            dataTokens: new RouteValueDictionary(new { today = "Friday" }),
            inlineConstraintResolver: _inlineConstraintResolver);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(routeValues);

        Assert.True(routeValues.ContainsKey("country"));
        Assert.Equal("USA", routeValues["country"]);
        Assert.True(routeValues.ContainsKey("id"));
        Assert.Equal("5", routeValues["id"]);

        Assert.True(context.RouteData.Values.ContainsKey("country"));
        Assert.Equal("USA", context.RouteData.Values["country"]);
        Assert.True(context.RouteData.Values.ContainsKey("id"));
        Assert.Equal("5", context.RouteData.Values["id"]);
        Assert.Same(originalRouteDataValues, context.RouteData.Values);

        Assert.Equal("Contoso", context.RouteData.DataTokens["company"]);
        Assert.Equal("Friday", context.RouteData.DataTokens["today"]);
        Assert.Same(originalDataTokens, context.RouteData.DataTokens);
    }

    [Fact]
    public async Task RouteAsync_MergesExistingRouteData_PassedToConstraint()
    {
        // Arrange
        var template = "{controller}/{action}/{id:int}";

        var context = CreateRouteContext("/Home/Index/5");
        var originalRouteDataValues = context.RouteData.Values;
        originalRouteDataValues.Add("country", "USA");

        var originalDataTokens = context.RouteData.DataTokens;
        originalDataTokens.Add("company", "Contoso");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var constraint = new CapturingConstraint();

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: new RouteValueDictionary(new { action = constraint }),
            dataTokens: new RouteValueDictionary(new { today = "Friday" }),
            inlineConstraintResolver: _inlineConstraintResolver);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(routeValues);

        Assert.True(routeValues.ContainsKey("country"));
        Assert.Equal("USA", routeValues["country"]);
        Assert.True(routeValues.ContainsKey("id"));
        Assert.Equal("5", routeValues["id"]);

        Assert.True(constraint.Values.ContainsKey("country"));
        Assert.Equal("USA", constraint.Values["country"]);
        Assert.True(constraint.Values.ContainsKey("id"));
        Assert.Equal("5", constraint.Values["id"]);

        Assert.True(context.RouteData.Values.ContainsKey("country"));
        Assert.Equal("USA", context.RouteData.Values["country"]);
        Assert.True(context.RouteData.Values.ContainsKey("id"));
        Assert.Equal("5", context.RouteData.Values["id"]);

        Assert.Equal("Contoso", context.RouteData.DataTokens["company"]);
        Assert.Equal("Friday", context.RouteData.DataTokens["today"]);
    }

    [Fact]
    public async Task RouteAsync_InlineConstraint_OptionalParameter()
    {
        // Arrange
        var template = "{controller}/{action}/{id:int?}";

        var context = CreateRouteContext("/Home/Index/5");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);

        Assert.NotEmpty(route.Constraints);
        Assert.IsType<OptionalRouteConstraint>(route.Constraints["id"]);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.True(routeValues.ContainsKey("id"));
        Assert.Equal("5", routeValues["id"]);

        Assert.True(context.RouteData.Values.ContainsKey("id"));
        Assert.Equal("5", context.RouteData.Values["id"]);
    }

    [Fact]
    public async Task RouteAsync_InlineConstraint_Regex()
    {
        // Arrange
        var template = @"{controller}/{action}/{ssn:regex(^\d{{3}}-\d{{3}}-\d{{4}}$)}";

        var context = CreateRouteContext("/Home/Index/123-456-7890");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);

        Assert.NotEmpty(route.Constraints);
        Assert.IsType<RegexInlineRouteConstraint>(route.Constraints["ssn"]);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.True(routeValues.ContainsKey("ssn"));
        Assert.Equal("123-456-7890", routeValues["ssn"]);

        Assert.True(context.RouteData.Values.ContainsKey("ssn"));
        Assert.Equal("123-456-7890", context.RouteData.Values["ssn"]);
    }

    [Fact]
    public async Task RouteAsync_InlineConstraint_OptionalParameter_NotPresent()
    {
        // Arrange
        var template = "{controller}/{action}/{id:int?}";

        var context = CreateRouteContext("/Home/Index");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);

        Assert.NotEmpty(route.Constraints);
        Assert.IsType<OptionalRouteConstraint>(route.Constraints["id"]);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.NotNull(routeValues);
        Assert.False(routeValues.ContainsKey("id"));
        Assert.False(context.RouteData.Values.ContainsKey("id"));
    }

    [Fact]
    public async Task RouteAsync_InlineConstraint_OptionalParameter_WithInConstructorConstraint()
    {
        // Arrange
        var template = "{controller}/{action}/{id:int?}";

        var context = CreateRouteContext("/Home/Index/5");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var constraints = new Dictionary<string, object>();
        constraints.Add("id", new RangeRouteConstraint(1, 20));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: constraints,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);

        Assert.NotEmpty(route.Constraints);
        Assert.IsType<OptionalRouteConstraint>(route.Constraints["id"]);
        var innerConstraint = ((OptionalRouteConstraint)route.Constraints["id"]).InnerConstraint;
        Assert.IsType<CompositeRouteConstraint>(innerConstraint);
        var compositeConstraint = (CompositeRouteConstraint)innerConstraint;
        Assert.Equal(2, compositeConstraint.Constraints.Count<IRouteConstraint>());

        Assert.Single(compositeConstraint.Constraints, c => c is IntRouteConstraint);
        Assert.Single(compositeConstraint.Constraints, c => c is RangeRouteConstraint);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.True(routeValues.ContainsKey("id"));
        Assert.Equal("5", routeValues["id"]);

        Assert.True(context.RouteData.Values.ContainsKey("id"));
        Assert.Equal("5", context.RouteData.Values["id"]);
    }

    [Fact]
    public async Task RouteAsync_InlineConstraint_OptionalParameter_ConstraintFails()
    {
        // Arrange
        var template = "{controller}/{action}/{id:range(1,20)?}";

        var context = CreateRouteContext("/Home/Index/100");

        IDictionary<string, object> routeValues = null;
        var mockTarget = new Mock<IRouter>(MockBehavior.Strict);
        mockTarget
            .Setup(s => s.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>(ctx =>
            {
                routeValues = ctx.RouteData.Values;
                ctx.Handler = NullHandler;
            })
            .Returns(Task.FromResult(true));

        var route = new Route(
            mockTarget.Object,
            template,
            defaults: null,
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);

        Assert.NotEmpty(route.Constraints);
        Assert.IsType<OptionalRouteConstraint>(route.Constraints["id"]);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.Handler);
    }

    // PathString in HttpAbstractions guarantees a leading slash - so no value in testing other cases.
    [Fact]
    public async Task Match_Success_LeadingSlash()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateRouteContext("/Home/Index");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Equal(2, context.RouteData.Values.Count);
        Assert.Equal("Home", context.RouteData.Values["controller"]);
        Assert.Equal("Index", context.RouteData.Values["action"]);
    }

    [Fact]
    public async Task Match_Success_RootUrl()
    {
        // Arrange
        var route = CreateRoute("");
        var context = CreateRouteContext("/");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Empty(context.RouteData.Values);
    }

    [Fact]
    public async Task Match_Success_Defaults()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}", new { action = "Index" });
        var context = CreateRouteContext("/Home");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Equal(2, context.RouteData.Values.Count);
        Assert.Equal("Home", context.RouteData.Values["controller"]);
        Assert.Equal("Index", context.RouteData.Values["action"]);
    }

    [Fact]
    public async Task Match_Success_CopiesDataTokens()
    {
        // Arrange
        var route = CreateRoute(
            "{controller}/{action}",
            defaults: new { action = "Index" },
            dataTokens: new { culture = "en-CA" });

        var context = CreateRouteContext("/Home");

        // Act
        await route.RouteAsync(context);
        Assert.NotNull(context.Handler);

        // This should not affect the route - RouteData.DataTokens is a copy
        context.RouteData.DataTokens.Add("company", "contoso");

        // Assert
        Assert.Single(route.DataTokens);
        Assert.Single(route.DataTokens, kvp => kvp.Key == "culture" && ((string)kvp.Value) == "en-CA");
    }

    [Fact]
    public async Task Match_Fails()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateRouteContext("/Home");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.Handler);
    }

    [Fact]
    public async Task Match_RejectedByHandler()
    {
        // Arrange
        var route = CreateRoute("{controller}", handleRequest: false);
        var context = CreateRouteContext("/Home");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.Handler);

        var value = Assert.Single(context.RouteData.Values);
        Assert.Equal("controller", value.Key);
        Assert.Equal("Home", Assert.IsType<string>(value.Value));
    }

    [Fact]
    public async Task Match_SetsRouters()
    {
        // Arrange
        var target = CreateTarget(handleRequest: true);
        var route = CreateRoute(target, "{controller}");
        var context = CreateRouteContext("/Home");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Single(context.RouteData.Routers);
        Assert.Same(target, context.RouteData.Routers[0]);
    }

    [Fact]
    public async Task Match_RouteValuesDoesntThrowOnKeyNotFound()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateRouteContext("/Home/Index");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.RouteData.Values["1controller"]);
    }

    [Fact]
    public async Task Match_Success_OptionalParameter_ValueProvided()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}.{format?}", new { action = "Index" });
        var context = CreateRouteContext("/Home/Create.xml");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Equal(3, context.RouteData.Values.Count);
        Assert.Equal("Home", context.RouteData.Values["controller"]);
        Assert.Equal("Create", context.RouteData.Values["action"]);
        Assert.Equal("xml", context.RouteData.Values["format"]);
    }

    [Fact]
    public async Task Match_Success_OptionalParameter_ValueNotProvided()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}.{format?}", new { action = "Index" });
        var context = CreateRouteContext("/Home/Create");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Equal(2, context.RouteData.Values.Count);
        Assert.Equal("Home", context.RouteData.Values["controller"]);
        Assert.Equal("Create", context.RouteData.Values["action"]);
    }

    [Fact]
    public async Task Match_Success_OptionalParameter_DefaultValue()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}.{format?}", new { action = "Index", format = "xml" });
        var context = CreateRouteContext("/Home/Create");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.NotNull(context.Handler);
        Assert.Equal(3, context.RouteData.Values.Count);
        Assert.Equal("Home", context.RouteData.Values["controller"]);
        Assert.Equal("Create", context.RouteData.Values["action"]);
        Assert.Equal("xml", context.RouteData.Values["format"]);
    }

    [Fact]
    public async Task Match_Success_OptionalParameter_EndsWithDot()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}.{format?}", new { action = "Index" });
        var context = CreateRouteContext("/Home/Create.");

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.Handler);
    }

    private static RouteContext CreateRouteContext(string requestPath, ILoggerFactory factory = null)
    {
        if (factory == null)
        {
            factory = NullLoggerFactory.Instance;
        }

        var request = new Mock<HttpRequest>(MockBehavior.Strict);
        request.SetupGet(r => r.Path).Returns(requestPath);

        var context = new Mock<HttpContext>(MockBehavior.Strict);
        context.Setup(m => m.RequestServices.GetService(typeof(ILoggerFactory)))
            .Returns(factory);
        context.SetupGet(c => c.Request).Returns(request.Object);

        return new RouteContext(context.Object);
    }

    [Fact]
    public void GetVirtualPath_Success()
    {
        // Arrange
        var route = CreateRoute("{controller}");
        var context = CreateVirtualPathContext(new { controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_Fail()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(new { controller = "Home" });

        // Act
        var path = route.GetVirtualPath(context);

        // Assert
        Assert.Null(path);
    }

    [Fact]
    public void GetVirtualPath_EncodesValues()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(
            new { name = "name with %special #characters" },
            new { controller = "Home", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index?name=name%20with%20%25special%20%23characters", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_AlwaysUsesDefaultUrlEncoder()
    {
        // Arrange
        var nameRouteValue = "name with %special #characters Jörn";
        var expected = "/Home/Index?name=" + UrlEncoder.Default.Encode(nameRouteValue);
        var services = new ServiceCollection();
        services.AddSingleton<ILoggerFactory>(NullLoggerFactory.Instance);
        services.AddOptions();
        services.AddRouting();
        // This test encoder should not be used by Routing and should always use the default one.
        services.AddSingleton<UrlEncoder>(new UrlTestEncoder());
        var httpContext = new DefaultHttpContext
        {
            RequestServices = services.BuildServiceProvider(),
        };

        var context = new VirtualPathContext(
            httpContext,
            values: new RouteValueDictionary(new { name = nameRouteValue }),
            ambientValues: new RouteValueDictionary(new { controller = "Home", action = "Index" }));

        var route = CreateRoute("{controller}/{action}");

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal(expected, pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_ForListOfStrings()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(
            new { color = new List<string> { "red", "green", "blue" } },
            new { controller = "Home", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index?color=red&color=green&color=blue", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_ForListOfInts()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(
            new { items = new List<int> { 10, 20, 30 } },
            new { controller = "Home", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index?items=10&items=20&items=30", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_ForList_Empty()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(
            new { color = new List<string> { } },
            new { controller = "Home", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_ForList_StringWorkaround()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(
            new { page = 1, color = new List<string> { "red", "green", "blue" }, message = "textfortest" },
            new { controller = "Home", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index?page=1&color=red&color=green&color=blue&message=textfortest", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Theory]
    [MemberData(nameof(DataTokensTestData))]
    public void GetVirtualPath_ReturnsDataTokens_WhenTargetReturnsVirtualPathData(
        RouteValueDictionary dataTokens)
    {
        // Arrange
        var path = "/TestPath";

        var target = new Mock<IRouter>(MockBehavior.Strict);
        target
            .Setup(r => r.GetVirtualPath(It.IsAny<VirtualPathContext>()))
            .Returns(() => new VirtualPathData(target.Object, path, dataTokens));

        var routeDataTokens =
            new RouteValueDictionary() { { "ThisShouldBeIgnored", "" } };

        var route = CreateRoute(
            target.Object,
            "{controller}",
            defaults: null,
            dataTokens: routeDataTokens);
        var context = CreateVirtualPathContext(new { controller = path });

        var expectedDataTokens = dataTokens ?? new RouteValueDictionary();

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Same(target.Object, pathData.Router);
        Assert.Equal(path, pathData.VirtualPath);
        Assert.NotNull(pathData.DataTokens);

        Assert.DoesNotContain(routeDataTokens.First().Key, pathData.DataTokens.Keys);

        Assert.Equal(expectedDataTokens.Count, pathData.DataTokens.Count);
        foreach (var dataToken in expectedDataTokens)
        {
            Assert.True(pathData.DataTokens.ContainsKey(dataToken.Key));
            Assert.Equal(dataToken.Value, pathData.DataTokens[dataToken.Key]);
        }
    }

    [Theory]
    [MemberData(nameof(DataTokensTestData))]
    public void GetVirtualPath_ReturnsDataTokens_WhenTargetReturnsNullVirtualPathData(
        RouteValueDictionary dataTokens)
    {
        // Arrange
        var path = "/TestPath";

        var target = new Mock<IRouter>(MockBehavior.Strict);
        target
            .Setup(r => r.GetVirtualPath(It.IsAny<VirtualPathContext>()))
            .Returns(() => null);

        var route = CreateRoute(
            target.Object,
            "{controller}",
            defaults: null,
            dataTokens: dataTokens);
        var context = CreateVirtualPathContext(new { controller = path });

        var expectedDataTokens = dataTokens ?? new RouteValueDictionary();

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Same(route, pathData.Router);
        Assert.Equal(path, pathData.VirtualPath);
        Assert.NotNull(pathData.DataTokens);

        Assert.Equal(expectedDataTokens.Count, pathData.DataTokens.Count);
        foreach (var dataToken in expectedDataTokens)
        {
            Assert.True(pathData.DataTokens.ContainsKey(dataToken.Key));
            Assert.Equal(dataToken.Value, pathData.DataTokens[dataToken.Key]);
        }
    }

    [Fact]
    public void GetVirtualPath_ValuesRejectedByHandler_StillGeneratesPath()
    {
        // Arrange
        var route = CreateRoute("{controller}", handleRequest: false);
        var context = CreateVirtualPathContext(new { controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_Success_AmbientValues()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}");
        var context = CreateVirtualPathContext(new { action = "Index" }, new { controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void RouteGenerationRejectsConstraints()
    {
        // Arrange
        var context = CreateVirtualPathContext(new { p1 = "abcd" });

        var route = CreateRoute(
            "{p1}/{p2}",
            new { p2 = "catchall" },
            true,
            new RouteValueDictionary(new { p2 = "\\d{4}" }));

        // Act
        var virtualPath = route.GetVirtualPath(context);

        // Assert
        Assert.Null(virtualPath);
    }

    [Fact]
    public void RouteGenerationAcceptsConstraints()
    {
        // Arrange
        var context = CreateVirtualPathContext(new { p1 = "hello", p2 = "1234" });

        var route = CreateRoute(
            "{p1}/{p2}",
            new { p2 = "catchall" },
            true,
            new RouteValueDictionary(new { p2 = "\\d{4}" }));

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/hello/1234", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void RouteWithCatchAllRejectsConstraints()
    {
        // Arrange
        var context = CreateVirtualPathContext(new { p1 = "abcd" });

        var route = CreateRoute(
            "{p1}/{*p2}",
            new { p2 = "catchall" },
            true,
            new RouteValueDictionary(new { p2 = "\\d{4}" }));

        // Act
        var virtualPath = route.GetVirtualPath(context);

        // Assert
        Assert.Null(virtualPath);
    }

    [Fact]
    public void RouteWithCatchAllAcceptsConstraints()
    {
        // Arrange
        var context = CreateVirtualPathContext(new { p1 = "hello", p2 = "1234" });

        var route = CreateRoute(
            "{p1}/{*p2}",
            new { p2 = "catchall" },
            true,
            new RouteValueDictionary(new { p2 = "\\d{4}" }));

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/hello/1234", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPathWithNonParameterConstraintReturnsUrlWithoutQueryString()
    {
        // Arrange
        var context = CreateVirtualPathContext(new { p1 = "hello", p2 = "1234" });

        var target = new Mock<IRouteConstraint>();
        target
            .Setup(
                e => e.Match(
                    It.IsAny<HttpContext>(),
                    It.IsAny<IRouter>(),
                    It.IsAny<string>(),
                    It.IsAny<RouteValueDictionary>(),
                    It.IsAny<RouteDirection>()))
            .Returns(true)
            .Verifiable();

        var route = CreateRoute(
            "{p1}/{p2}",
            new { p2 = "catchall" },
            true,
            new RouteValueDictionary(new { p2 = target.Object }));

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/hello/1234", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);

        target.VerifyAll();
    }

    // Any ambient values from the current request should be visible to constraint, even
    // if they have nothing to do with the route generating a link
    [Fact]
    public void GetVirtualPath_ConstraintsSeeAmbientValues()
    {
        // Arrange
        var constraint = new CapturingConstraint();
        var route = CreateRoute(
            template: "slug/{controller}/{action}",
            defaults: null,
            handleRequest: true,
            constraints: new { c = constraint });

        var context = CreateVirtualPathContext(
            values: new { action = "Store" },
            ambientValues: new { Controller = "Home", action = "Blog", extra = "42" });

        var expectedValues = new RouteValueDictionary(
            new { controller = "Home", action = "Store", extra = "42" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/slug/Home/Store", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);

        Assert.Equal(expectedValues, constraint.Values);
    }

    // Non-parameter default values from the routing generating a link are not in the 'values'
    // collection when constraints are processed.
    [Fact]
    public void GetVirtualPath_ConstraintsDontSeeDefaults_WhenTheyArentParameters()
    {
        // Arrange
        var constraint = new CapturingConstraint();
        var route = CreateRoute(
            template: "slug/{controller}/{action}",
            defaults: new { otherthing = "17" },
            handleRequest: true,
            constraints: new { c = constraint });

        var context = CreateVirtualPathContext(
            values: new { action = "Store" },
            ambientValues: new { Controller = "Home", action = "Blog" });

        var expectedValues = new RouteValueDictionary(
            new { controller = "Home", action = "Store" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/slug/Home/Store", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);

        Assert.Equal(expectedValues, constraint.Values);
    }

    // Default values are visible to the constraint when they are used to fill a parameter.
    [Fact]
    public void GetVirtualPath_ConstraintsSeesDefault_WhenThereItsAParameter()
    {
        // Arrange
        var constraint = new CapturingConstraint();
        var route = CreateRoute(
            template: "slug/{controller}/{action}",
            defaults: new { action = "Index" },
            handleRequest: true,
            constraints: new { c = constraint });

        var context = CreateVirtualPathContext(
            values: new { controller = "Shopping" },
            ambientValues: new { Controller = "Home", action = "Blog" });

        var expectedValues = new RouteValueDictionary(
            new { controller = "Shopping", action = "Index" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/slug/Shopping", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);

        Assert.Equal(expectedValues, constraint.Values);
    }

    // Default values from the routing generating a link are in the 'values' collection when
    // constraints are processed - IFF they are specified as values or ambient values.
    [Fact]
    public void GetVirtualPath_ConstraintsSeeDefaults_IfTheyAreSpecifiedOrAmbient()
    {
        // Arrange
        var constraint = new CapturingConstraint();
        var route = CreateRoute(
            template: "slug/{controller}/{action}",
            defaults: new { otherthing = "17", thirdthing = "13" },
            handleRequest: true,
            constraints: new { c = constraint });

        var context = CreateVirtualPathContext(
            values: new { action = "Store", thirdthing = "13" },
            ambientValues: new { Controller = "Home", action = "Blog", otherthing = "17" });

        var expectedValues = new RouteValueDictionary(
            new { controller = "Home", action = "Store", otherthing = "17", thirdthing = "13" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/slug/Home/Store", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);

        Assert.Equal(expectedValues.OrderBy(kvp => kvp.Key), constraint.Values.OrderBy(kvp => kvp.Key));
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_Success()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", id = 4 });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/4", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_NonMatchingvalue()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", id = "asf" });

        // Act
        var path = route.GetVirtualPath(context);

        // Assert
        Assert.Null(path);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_OptionalParameter_ValuePresent()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int?}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", id = 98 });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/98", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_OptionalParameter_ValueNotPresent()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int?}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_OptionalParameter_ValuePresent_ConstraintFails()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int?}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", id = "sdfd" });

        // Act
        var path = route.GetVirtualPath(context);

        // Assert
        Assert.Null(path);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_CompositeInlineConstraint()
    {
        // Arrange
        var route = CreateRoute("{controller}/{action}/{id:int:range(1,20)}");
        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", id = 14 });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/14", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_InlineConstraints_CompositeConstraint_FromConstructor()
    {
        // Arrange
        var constraint = new MaxLengthRouteConstraint(20);
        var route = CreateRoute(
            template: "{controller}/{action}/{name:alpha}",
            defaults: null,
            handleRequest: true,
            constraints: new { name = constraint });

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_ParameterPresentInValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name}.{format?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products", format = "xml" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products.xml", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_ParameterNotPresentInValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name}.{format?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_ParameterPresentInValuesAndDefaults()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name}.{format?}",
            defaults: new { format = "json" },
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products", format = "xml" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products.xml", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_ParameterNotPresentInValues_PresentInDefaults()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name}.{format?}",
            defaults: new { format = "json" },
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_ParameterNotPresentInTemplate_PresentInValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products", format = "json" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/products?format=json", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_FollowedByDotAfterSlash_ParameterPresent()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/.{name?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home", name = "products" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/.products", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_FollowedByDotAfterSlash_ParameterNotPresent()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/.{name?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index/", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameter_InSimpleSegment()
    {
        // Arrange
        var route = CreateRoute(
            template: "{controller}/{action}/{name?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { action = "Index", controller = "Home" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.Equal("/Home/Index", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_TwoOptionalParameters_OneValueFromAmbientValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "a/{b=15}/{c?}/{d?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { },
            ambientValues: new { c = "17" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/a/15/17", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_OptionalParameterAfterDefault_OneValueFromAmbientValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "a/{b=15}/{c?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { },
            ambientValues: new { c = "17" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/a/15/17", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_TwoOptionalParametersAfterDefault_OneValueFromAmbientValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "a/{b=15}/{c?}/{d?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { },
            ambientValues: new { c = "17" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/a/15/17", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    [Fact]
    public void GetVirtualPath_TwoOptionalParametersAfterDefault_LastValueFromAmbientValues()
    {
        // Arrange
        var route = CreateRoute(
            template: "a/{b=15}/{c?}/{d?}",
            defaults: null,
            handleRequest: true,
            constraints: null);

        var context = CreateVirtualPathContext(
            values: new { },
            ambientValues: new { d = "17" });

        // Act
        var pathData = route.GetVirtualPath(context);

        // Assert
        Assert.NotNull(pathData);
        Assert.Equal("/a", pathData.VirtualPath);
        Assert.Same(route, pathData.Router);
        Assert.Empty(pathData.DataTokens);
    }

    private static VirtualPathContext CreateVirtualPathContext(object values)
    {
        return CreateVirtualPathContext(new RouteValueDictionary(values), null);
    }

    private static VirtualPathContext CreateVirtualPathContext(object values, object ambientValues)
    {
        return CreateVirtualPathContext(new RouteValueDictionary(values), new RouteValueDictionary(ambientValues));
    }

    private static VirtualPathContext CreateVirtualPathContext(
        RouteValueDictionary values,
        RouteValueDictionary ambientValues)
    {
        var services = new ServiceCollection();
        services.AddSingleton<ILoggerFactory>(NullLoggerFactory.Instance);
        services.AddOptions();
        services.AddRouting();

        var context = new DefaultHttpContext
        {
            RequestServices = services.BuildServiceProvider(),
        };

        return new VirtualPathContext(context, ambientValues, values);
    }

    private static VirtualPathContext CreateVirtualPathContext(string routeName)
    {
        return new VirtualPathContext(null, null, null, routeName);
    }

    public static IEnumerable<object[]> DataTokens
    {
        get
        {
            yield return new object[] {
                                            new Dictionary<string, object> { { "key1", "data1" }, { "key2", 13 } },
                                            new Dictionary<string, object> { { "key1", "data1" }, { "key2", 13 } },
                                          };
            yield return new object[] {
                                            new RouteValueDictionary { { "key1", "data1" }, { "key2", 13 } },
                                            new Dictionary<string, object> { { "key1", "data1" }, { "key2", 13 } },
                                          };
            yield return new object[] {
                                            new object(),
                                            new Dictionary<string,object>(),
                                          };
            yield return new object[] {
                                            null,
                                            new Dictionary<string, object>()
                                          };
            yield return new object[] {
                                            new { key1 = "data1", key2 = 13 },
                                            new Dictionary<string, object> { { "key1", "data1" }, { "key2", 13 } },
                                          };
        }
    }

    [Theory]
    [MemberData(nameof(DataTokens))]
    public void RegisteringRoute_WithDataTokens_AbleToAddTheRoute(object dataToken,
                                                                  IDictionary<string, object> expectedDictionary)
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        // Act
        routeBuilder.MapRoute("mockName",
                              "{controller}/{action}",
                              defaults: null,
                              constraints: null,
                              dataTokens: dataToken);

        // Assert
        var templateRoute = (Route)routeBuilder.Routes[0];

        Assert.Equal(expectedDictionary.Count, templateRoute.DataTokens.Count);
        foreach (var expectedKey in expectedDictionary.Keys)
        {
            Assert.True(templateRoute.DataTokens.ContainsKey(expectedKey));
            Assert.Equal(expectedDictionary[expectedKey], templateRoute.DataTokens[expectedKey]);
        }
    }

    [Fact]
    public void RegisteringRoute_WithParameterPolicy_AbleToAddTheRoute()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        // Act
        routeBuilder.MapRoute("mockName",
                              "{controller:test-policy}/{action}");

        // Assert
        var templateRoute = (Route)routeBuilder.Routes[0];

        Assert.Empty(templateRoute.Constraints);
    }

    [Fact]
    public void RegisteringRouteWithInvalidConstraints_Throws()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        // Assert
        var expectedMessage = "An error occurred while creating the route with name 'mockName' and template" +
            " '{controller}/{action}'.";

        var exception = ExceptionAssert.Throws<RouteCreationException>(
            () => routeBuilder.MapRoute("mockName",
                "{controller}/{action}",
                defaults: null,
                constraints: new { controller = "a.*", action = 17 }),
                expectedMessage);

        expectedMessage = "The constraint entry 'action' - '17' on the route '{controller}/{action}' " +
            "must have a string value or be of a type which implements '" +
            typeof(IRouteConstraint) + "'.";
        Assert.NotNull(exception.InnerException);
        Assert.Equal(expectedMessage, exception.InnerException.Message);
    }

    [Fact]
    public void RegisteringRouteWithTwoConstraints()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        var mockConstraint = new Mock<IRouteConstraint>().Object;

        routeBuilder.MapRoute("mockName",
            "{controller}/{action}",
            defaults: null,
            constraints: new { controller = "a.*", action = mockConstraint });

        var constraints = ((Route)routeBuilder.Routes[0]).Constraints;

        // Assert
        Assert.Equal(2, constraints.Count);
        Assert.IsType<RegexRouteConstraint>(constraints["controller"]);
        Assert.Equal(mockConstraint, constraints["action"]);
    }

    [Fact]
    public void RegisteringRouteWithOneInlineConstraintAndOneUsingConstraintArgument()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        // Act
        routeBuilder.MapRoute("mockName",
            "{controller}/{action}/{id:int}",
            defaults: null,
            constraints: new { id = "1*" });

        // Assert
        var constraints = ((Route)routeBuilder.Routes[0]).Constraints;
        Assert.Single(constraints);
        var constraint = (CompositeRouteConstraint)constraints["id"];
        Assert.IsType<CompositeRouteConstraint>(constraint);
        Assert.IsType<RegexRouteConstraint>(constraint.Constraints.ElementAt(0));
        Assert.IsType<IntRouteConstraint>(constraint.Constraints.ElementAt(1));
    }

    [Fact]
    public void RegisteringRoute_WithOneInlineConstraint_AddsItToConstraintCollection()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        // Act
        routeBuilder.MapRoute("mockName",
            "{controller}/{action}/{id:int}",
            defaults: null,
            constraints: null);

        // Assert
        var constraints = ((Route)routeBuilder.Routes[0]).Constraints;
        Assert.Single(constraints);
        Assert.IsType<IntRouteConstraint>(constraints["id"]);
    }

    [Fact]
    public void RegisteringRouteWithRouteName_WithNullDefaults_AddsTheRoute()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        routeBuilder.MapRoute(name: "RouteName", template: "{controller}/{action}", defaults: null);

        // Act
        var name = ((Route)routeBuilder.Routes[0]).Name;

        // Assert
        Assert.Equal("RouteName", name);
    }

    [Fact]
    public void RegisteringRouteWithRouteName_WithNullDefaultsAndConstraints_AddsTheRoute()
    {
        // Arrange
        var routeBuilder = CreateRouteBuilder();

        routeBuilder.MapRoute(name: "RouteName",
                            template: "{controller}/{action}",
                            defaults: null,
                            constraints: null);

        // Act
        var name = ((Route)routeBuilder.Routes[0]).Name;

        // Assert
        Assert.Equal("RouteName", name);
    }

    [Theory]
    [InlineData("///")]
    [InlineData("/a//")]
    [InlineData("/a/b//")]
    [InlineData("//b//")]
    [InlineData("///c")]
    [InlineData("///c/")]
    public async Task RouteAsync_MultipleOptionalParameters_WithEmptyIntermediateSegmentsDoesNotMatch(string url)
    {
        // Arrange
        var builder = CreateRouteBuilder();

        builder.MapRoute(name: null,
                template: "{controller?}/{action?}/{id?}",
                defaults: null,
                constraints: null);

        var route = builder.Build();

        var context = CreateRouteContext(url);

        // Act
        await route.RouteAsync(context);

        // Assert
        Assert.Null(context.Handler);
    }

    // DataTokens test data for TemplateRoute.GetVirtualPath
    public static IEnumerable<object[]> DataTokensTestData
    {
        get
        {
            yield return new object[] { null };
            yield return new object[] { new RouteValueDictionary() };
            yield return new object[] { new RouteValueDictionary() { { "tokenKeyA", "tokenValueA" } } };
        }
    }

    private static IRouteBuilder CreateRouteBuilder()
    {
        var services = new ServiceCollection();
        services.AddSingleton<IInlineConstraintResolver>(_inlineConstraintResolver);
        services.AddSingleton<RoutingMarkerService>();
        services.AddSingleton<ParameterPolicyFactory, DefaultParameterPolicyFactory>();
        services.Configure<RouteOptions>(ConfigureRouteOptions);

        var applicationBuilder = Mock.Of<IApplicationBuilder>();
        applicationBuilder.ApplicationServices = services.BuildServiceProvider();

        var routeBuilder = new RouteBuilder(applicationBuilder);
        routeBuilder.DefaultHandler = new RouteHandler(NullHandler);
        return routeBuilder;
    }

    private static Route CreateRoute(string routeName, string template, bool handleRequest = true)
    {
        return new Route(
            CreateTarget(handleRequest),
            routeName,
            template,
            defaults: null,
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);
    }

    private static Route CreateRoute(string template, bool handleRequest = true)
    {
        return new Route(CreateTarget(handleRequest), template, _inlineConstraintResolver);
    }

    private static Route CreateRoute(
        string template,
        object defaults,
        bool handleRequest = true,
        object constraints = null,
        object dataTokens = null)
    {
        return new Route(
            CreateTarget(handleRequest),
            template,
            new RouteValueDictionary(defaults),
            new RouteValueDictionary(constraints),
            new RouteValueDictionary(dataTokens),
            _inlineConstraintResolver);
    }

    private static Route CreateRoute(IRouter target, string template)
    {
        return new Route(
            target,
            template,
            new RouteValueDictionary(),
            constraints: null,
            dataTokens: null,
            inlineConstraintResolver: _inlineConstraintResolver);
    }

    private static Route CreateRoute(
        IRouter target,
        string template,
        object defaults,
        RouteValueDictionary dataTokens = null)
    {
        return new Route(
            target,
            template,
            new RouteValueDictionary(defaults),
            constraints: null,
            dataTokens: dataTokens,
            inlineConstraintResolver: _inlineConstraintResolver);
    }

    private static IRouter CreateTarget(bool handleRequest = true)
    {
        var target = new Mock<IRouter>(MockBehavior.Strict);
        target
            .Setup(e => e.GetVirtualPath(It.IsAny<VirtualPathContext>()))
            .Returns<VirtualPathContext>(rc => null);

        target
            .Setup(e => e.RouteAsync(It.IsAny<RouteContext>()))
            .Callback<RouteContext>((c) => c.Handler = handleRequest ? NullHandler : null)
            .Returns(Task.FromResult<object>(null));

        return target.Object;
    }

    private static IInlineConstraintResolver GetInlineConstraintResolver()
    {
        var routeOptions = new RouteOptions();
        ConfigureRouteOptions(routeOptions);

        var routeOptionsMock = new Mock<IOptions<RouteOptions>>();
        routeOptionsMock
            .SetupGet(o => o.Value)
            .Returns(routeOptions);

        return new DefaultInlineConstraintResolver(routeOptionsMock.Object, new TestServiceProvider());
    }

    private static void ConfigureRouteOptions(RouteOptions options)
    {
        options.ConstraintMap["test-policy"] = typeof(TestPolicy);
        options.SetParameterPolicy<RegexInlineRouteConstraint>("regex");
    }

    private class TestPolicy : IParameterPolicy
    {
    }
}
