Question

Given the following example code, how can I configure Pex to respect my Code Contracts?

    public static IEnumerable<User> Administrators(this UserGroup userGroup)
    {
        Contract.Requires(userGroup != null);
        Contract.Requires(userGroup.UserList != null);

        return userGroup.UserList.Where(ul => ul.IsAdmin == true);
    }

Current Problem: When I run Pex, it’s still generating test cases which violate the specified code contracts.

FYI: Here are the ‘Code Contracts’ settings in my csproj file.

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EDIT: Did something break in SP1?

Answer 1

First you need to use a typed version of Requires

use ArgumentNullException as T

Also in you project properties you need to tell code cotracts to use the standard rewriter. DO NOT click assert on failure 😉

Contract.Requires<ArgumentNullException>(i != null);

then your code will throw an argumetn null exception and pex can add an attribute to your pexmethod to say that it is allowed to throw it and will create a passing test that throws the exception

you can then promote those and save the unit tests