ASP.net MVC单元测试中的模拟路由约束

Question

I am trying to use Moq to test a route with a constraint. I am not testing the constraint, but the route and want to just return true for when the route is tested as part of the route test. The following code is an attempt to mock the constraint in the test setting it to always return true.

Mock<SomeRouteConstraint> routeConstraint = new Mock<SomeRouteConstraint>();
routeConstraint.Setup(tC => tC.Match(It.IsAny<HttpContextBase>(), It.IsAny<Route>(), It.IsAny<string>(), It.IsAny<RouteValueDictionary>(), It.IsAny<RouteDirection>())).Returns(true);

context.Setup(ctx => ctx.Request.AppRelativeCurrentExecutionFilePath).Returns("someurl/thatmaps/toavalue");

RouteData routeData = routes.GetRouteData(context.Object);

Assert.IsNotNull(routeData, "Did not find the route");

The code executes fine, but the actual constraint is tested instead of just returning true per the Mock.

Here is the sample route:

            Routes.Add("someroutewithconstraint",
            new LowercaseRoute("{someurl}/{thatmaps}/{toavalue}",
            new { controller = "SomeController", action = "SomeAction" },
            new {  
                  someConstraint = new SomeRouteConstraint()
            },
            new LowercaseRouteHandler());

The real question here is actually how to use the Mocked route constraint instead of the real constraint. Is there something on the context that allows Moq to override route contraints?

Answer 1

Solved this by creating a class to attach constrain names to http items collection. Then we override the ProcessConstraint method in our own Route and check the collection for constraints to skip (each one can be set to true or false). Remember we are testing the route not the constraint.

    protected override bool ProcessConstraint(System.Web.HttpContextBase httpContext, object constraint, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    {
        bool retValue = false;
        string contraintName = constraint.GetType().Name;

        if (httpContext.Items != null && httpContext.Items.Contains(contraintName))
        {
            //Inspect list of constraints to override
            if (httpContext.Items.Contains(constraint.GetType().Name))
                bool.TryParse(httpContext.Items[constraint.GetType().Name].ToString(), out retValue);
        }
        else
        {
            retValue = base.ProcessConstraint(httpContext, constraint, parameterName, DecodeValues(values), routeDirection);
        }

        return retValue;
    }