R – target Silverlight 3.0 using NAnt

There is actually a (subtle) difference between the two. Imagine you have the following code in File1.cs:

// File1.cs
using System;
namespace Outer.Inner
{
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now imagine that someone adds another file (File2.cs) to the project that looks like this:

// File2.cs
namespace Outer
{
    class Math
    {
    }
}

The compiler searches Outer before looking at those using directives outside the namespace, so it finds Outer.Math instead of System.Math. Unfortunately (or perhaps fortunately?), Outer.Math has no PI member, so File1 is now broken.

This changes if you put the using inside your namespace declaration, as follows:

// File1b.cs
namespace Outer.Inner
{
    using System;
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now the compiler searches System before searching Outer, finds System.Math, and all is well.

Some would argue that Math might be a bad name for a user-defined class, since there's already one in System; the point here is just that there is a difference, and it affects the maintainability of your code.

It's also interesting to note what happens if Foo is in namespace Outer, rather than Outer.Inner. In that case, adding Outer.Math in File2 breaks File1 regardless of where the using goes. This implies that the compiler searches the innermost enclosing namespace before it looks at any using directive.

MSBuild is a pretty good build tool. I've used it in combination with NAnt and Cruisecontrol.Net a couple of times. NAnt together with the NAnt contrib extensions seems a bit more flexible in handling OSS tools like NUnit, NCover etc while the fact that MSBuild can build VS solutions is a big plus for it. I found the easiest way to create build scripts is to use both, NAnt to call the different parts of the build (build, fxcop, test, coverage etc) and MSBuild to do the actual building.

I haven't got much good to say about MSTest. It's slow and cumbersome to install on for example a build server. It's not very flexible and has all kinds of 'extras' that seem more geared to integration testing than unit testing. I found light weight XUnit.Net, MBUnit or NUnit to be far better suited for unit testing. Speed is important here, you want to run the tests often for quick feedback on the effects of your changes in code. Portability is important too. You want to have the tests run everywhere without a lot of setup and hacking like you need for MSTest on a machine that doesn't have team system installed. Although Unit testing isn't new there's still a lot of development going on there. Best practices change a lot and so do the tools. I don't want to be tied to a tool that only gets upgraded every few years with visual studio. Every one of the three OSS .net unit testing tools is set up to be extensible. MSTest isn't (as far as i've seen).