Ensuring complete code coverage

The way I ensure complete code coverage (got this idea from Gordon Letwin many many years ago) is to place a trap in my code at the start of every new section of code, in every if & else, after a while & for, and anywhere else appropiate.

Then when the trap hits, it drops me in the debugger and I single step through the code until I get to code I've already walked through. This way I end up single stepping through every line of code I write. And by doing a grep for trap I can find code that has never been executed.

Here's the code to make this work in C#. To call it you just call Trap.trap();

using System;

namespace WindwardBear.utils

{

/// <summary>

/// This code will force a break in to the debugger for debug builds. For release builds they do nothing.

/// </summary>

public sealed class Trap

{

 

// can't create this

private Trap()

{

}

 

/// <summary>Will break in to the debugger (debug builds only).</summary>

public static void trap()

{

#if DEBUG

System.Diagnostics.Debugger.Break();

#endif

}

 

/// <summary>Will break in to the debugger if breakOn is true (debug builds only).</summary>

/// <param name="breakOn">Will break if this boolean value is true.</param>

public static void trap(Boolean breakOn)

{

#if DEBUG

if (breakOn)

System.Diagnostics.Debugger.Break();

#endif

}

}

}

Comments

[Stephen]

what about using a code coverage tool? NCover, PartCover, and any of the VS Team editions all support code coverage of .NET code.

[David Thielen]

Those are good tools too, but they serve a different purpose. With the TRAP I am dropped in to the debugger at that point in the code to step through it. And it gives me an easy way to walk each part as I first hit it, which can be days apart throughout a module.