eXtreme .NET: Introducing eXtreme Programming Techniques to .NET Developers [Electronic resources] نسخه متنی

How Do You Feel About TDD?

For the next exercise, we are going to build the same program twice. First, we are going to build the program without doing any tests, and then we are going to build the same program writing the tests first. We will then see how we feel about each program.

We are going to write some code to calculate some derived data from stock price data that is passed to our code. We are going to write a class library to encapsulate the calculations for other developers to use.

The library has to take a collection of prices and timestamps for a stock price and return the high and low prices for a given date. The collection is in the form of a HashTable containing DateTime objects mapping to double values to represent timestamps mapping to prices.

Exercise 4-10: Without Tests

I provide the skeleton for you, and then you can finish the exercise. This exercise should not take more than 30 minutes to complete.

using System;
using System.Collections.Specialized;
namespace NoTests
{
public class CalcClass
{
public void CalcHighLow(Hashtable DatePriceList,
DateTime day, ref decimal high, ref decimal low)
{
}
}
}

Exercise 4-11: With Tests

We are now going to do the same project again, this time by writing tests first. I will get you started, and then you can finish the exercise yourself. This exercise should not take you more than 30 minutes to complete.

using System;
namespace CsWithTests
{
public class CalcClass
{
}
}

using System;
using System.Collections;
using NUnit.Framework;
namespace CsWithTests
{
[TestFixture]
public class CalcTests
{
[Test]
public void TestCalcHighLow()
{
Hashtable datePriceList;
DateTime day;
Decimal high;
Decimal low;
CalcClass calc;
//calc.CalcHighLow(datePriceList, day, high, low);
}
}
}

Confidence Test

How do you feel after completing the last two exercises? Which class library are you more confident is correct?

If you have built meaningful tests, you should feel very confident with the second library. Even if you do not believe you have put much effort into the tests in the second exercise, the very fact that you have some means of validating your code should give you some extra level of certainty.

Visual Studio.NET 2005 Team System The next version of Visual Studio.NET will be available in several flavors. A group of these flavors is called Visual Studio.NET 2005 Team System. This group is aimed at the enterprise development community. Two of the products in this group will include an integrated unit-testing framework. This framework will be similar to NUnit. The two products that include the unit testing will be Visual Studio Team Developer and Visual Studio Team Tester. The beta of Visual Studio 2005 Team System indicates that the attributes you have learned in NUnit will differ slightly: TestFixture is called TestClass. Test is called TestMethod. SetUp is called TestInitialize. TearDown is called TestCleanup. The lessons you have learned in this chapter will all still hold true. It will be easy to move from NUnit to the unit-testing system in Visual Studio.NET Team System. The current plans indicate that the unit-testing tools will not be shipped with other versions of Visual Studio.NET 2005. Testing is a cornerstone of the XP practices. Testing is important to all the practices in this book. Is Microsoft making a mistake by not shipping unit-testing tools with all the versions of Visual Studio?