XUnit test for interface implementation

ValueObjectTest.cs

public class ValueObjectTest
{
    [Fact]
    public void AllValueObjectsImplementIEquatable()
    {
        var typeToFind = typeof (IValueObject);
        var typesFound = AppDomain.CurrentDomain.GetAssemblies().ToList()
            .SelectMany(s => s.GetTypes())
            .Where(typeToFind.IsAssignableFrom);

        foreach ( var type in typesFound)
        {
            if (type.IsInterface) continue;

            bool typeIsIEquatable = type.GetInterfaces().Any(
                i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof (IEquatable <>));

            Assert.True(typeIsIEquatable, string.Format( "{0} does not implement IEquatable<>",type));
        }
    }
}