Delphi 的单元测试工具DUnit

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本篇文章主要介绍了"Delphi 的单元测试工具DUnit",主要涉及到Delphi 的单元测试工具DUnit方面的内容,对于Delphi 的单元测试工具DUnit感兴趣的同学可以参考一下。 DUnit是XUnit家族中的一员,是Extreme Programming测试实现Xtreme Testing的一种工具。 DUnit的用法和JUnit很类似,如果有相关经验很容易上手。这里是DUnit的官方地址: ,下载地址: 将DUnit解压至任意目录(我习惯在D:/Study/DelphiLib/),打开Delphi 7,将DUnit路径添加到 Tools- > Environment Options 里面的 Library -> Library Path,这样DUnit就安装完成了。 如果有装过CnPack 的Delphi工具包,就可以很轻松的在 File -> New -> Other -> CnPack -> DUnit测试实例生成向导 中建立新的测试用例。 下面是我的一个简单的测试用例,测试AppFun中的 GetString() 和 Add() 方法。 TAppFun.pas (* UTest by Jason 2010-01-06 21:30 *) unit AppFun; interface uses SysUtils; type TAppFun = class(TObject) public class function GetString(sName: string; iAge: Integer): string; class function Add(iA: Integer; iB: Integer): Integer; end; implementation class function TAppFun.GetString(sName: string; iAge: Integer): string; begin result := 'Hello ' + sName + ', your age is ' + IntToStr(iAge); end; class function TAppFun.Add(iA: Integer; iB: Integer): Integer; begin Result := iA + iB; end; end. UTest.pas (* UTest by Jason 2010-01-06 21:30 *) unit UTest; interface uses Windows, SysUtils, Classes, TestFramework, TestExtensions; type TTest = class(TTestCase) protected procedure SetUp; override; procedure TearDown; override; published procedure Test; procedure TestGetString(); end; implementation uses AppFun, Dialogs; procedure TTest.Setup; begin ShowMessage('In Setup!'); end; procedure TTest.TearDown; begin ShowMessage('In TearDown!'); end; procedure TTest.Test; begin Self.Check(TAppFun.GetString('Jason', 22) = 'Hello Jason, your age is 22', 'Second Test'); end; procedure TTest.TestGetString(); begin Check(TAppFun.Add(3, 5) = 8, 'First Test'); end; initialization TestFramework.RegisterTest(TTest.Suite); end. 从上面的代码可以看出,XUnit系列风格都比较类似,很容易操作。   DUnit还有一些更高阶的操作,比如在控制台输出/在独立线程中运行测试/Exception测试等等,详细操作可以参考下列文档。目前我用到的就是简单的单元测试。 一点资料: DUnit 的官方地址 DUnit 下载地址DUnit 官方文档(英文)DUnit 官方文档(繁体中文)『Delphi园地』-Delphi单元测试工具Dunit介绍Delphi单元测试工具Dunit介绍_51Testing软件测试网 Delphi宝刀不老啊~呵呵~ 版权所有 © 2010 转载本站文章请注明: 转载自 Log4D 原文链接: 您可以随意地转载本站的文章,但是必须在醒目位置注明来源及本站链接,不可以将本站文章商业化使用,或者修改、转换或者以本作品为基础进行创作。 ============================================================================================================================ To err is human - Automated testing of Delphi code with DUnit. By Kris Golko To introduce bugs is human; the problem is usually not with fixing them, but with finding them before your clients do. Automated testing tools come to the rescue here, with their ability to repeat the testing process relentlessly, so developers can work with much more confidence. Why choose DUnit? Because it's about unit testing (unit in the sense of building a block of code rather than an Object Pascal unit). Another advantage is that DUnit tests are frameworks within which to execute code, which is faster and more convenient than running an entire application. What I like most in DUnit is that I can create my test cases with my favourite development tool. DUnit supports Delphi 4 through 7 as well as Kylix. Getting started DUnit is distributed as source code; it comprises a number of Delphi source files, examples and documentation. It can be downloaded from the project web page on SourceForge To install, just unzip the file into a directory of your choice, preserving subdirectories. The units used to create and run tests are in 'src' subdirectory which should either be added to the Library Path in 'Environment Options|Library' or the Search Path of Project|Options in your test project. How to write test cases This is easy: all you have to do is to create a class inherited from TTestCase, TTestCase is declared in the TestFramework unit. To add tests to a test case class, simply add a published procedure for each test to your derived class. A test runner object uses RTTI to detect what tests are available in a test case class. There are two very useful methods: Setup and TearDown. Execution of each individual test case within a class begins with Setup, then comes the published procedure which constitutes the test, which is then followed by TearDown. Setup can be used to instantiate objects needed to run tests and initialise their states according to the test's operations. Setup should also contain actions needed to be performed before every test is executed, like connecting to a database. TearDown method should be used to clean up and dispose of objects. A published procedure typically contains multiple calls to the Check method. The Check method is declared as follows: procedure Check(Condition: boolean; msg: string = ''); virtual; The condition parameter is usually in the form of an expression, which evaluates to a Boolean value. If the expression passed into the Check procedure evaluates to false then the test is marked as failed and the execution of the test is aborted. ... Check(Expected = Actual, 'Actual number different than expected'); ... Tests are organised in bundles, called suites. Test suites can contain multiple tests and other test suites, thus providing a way to build a tree of tests. Central to DUnit's operations is the test registry, which keeps all the suites in the test application. Typically, the test registry is built while a test application initialises. Units which declare test cases by convention have an initialization section where test cases are created and added to the registry. Test suites can be created by instantiating the TTestSuite class declared in the TestFramework. The most convenient and often used way to create a test suite is to use method Suite of TTestCase class, which creates a new TTestSuite containing only the TestCase: note that it's a class method. The RegisterTest and RegisterTests procedures add tests or test suites to the test registry. The simplest example is to create a test suite containing a single test case and then register it as follows: Framework.RegisterTest(TMyTest.Suite); How to run tests DUnit includes two standard test runner classes: TGUITestRunner with interactive GUI interface and TTextTestRunner with batch mode command line interface. TGUITestRunner is declared in the GUITestRunner unit along with the RunRegisteredTests standalone procedure, which runs the registered test suites using TGUITestRunner. The CLX version of TGUITextRunner is declared in the QGUITestRunner unit. TTextTestRunner is declared the TextTestRunner unit along with the corresponding RunRegisteredTests standalone procedure. Calls to RunRegisteredTest are usually qualified with a unit name, since there're multiple global RunRegisteredTests procedures, for example: GUITestRunner.RunRegisteredTest; Existing users of DUnit will notice that one of the more recent changes to DUnit is the addition of RunRegisteredTests class methods and the deprecation of standalone RunRegisteredTests, since multiple global procedures with the same name unnecessarily clutter the name space. The call to RunRegisteredTests is now recommended to be qualified with the test runner class name rather than a unit name: TGUITestRunner.RunRegisteredTest; An example Let's put it all into practice. The example application collects ratings in the way that many web sites provide a way to "rate this site". Most notably, CodeCentral has an interesting rating system where you can set choices according to your personal preferences (my favourite is Ancient Greek Mythology). The basic logic of our rating system is defined by the IRateCollector interface. IRatingCollector = interface   function GetPrompt: string;   procedure Rate(Rater: string; Choice: integer);   function GetChoiceCount: integer;   function GetChoice(Choice: integer): string;   function GetChoiceRatings(Choice: integer): integer;   function GetRatingCount: integer;   function GetRating(Index: integer; var Rater: string): integer;   function GetRatersRating(Rater: string): integer; end; The TRateTests class allows us to develop and test the business logic independently from developing the user interface. It's actually advantageous to develop and test the business logic before starting the user interface. The test cases are designed to test any implementation of IRatingCollector. TRateTests = class(TTestCase) private   FRateCollector: IRatingCollector; protected   procedure Setup; override;   procedure TearDown; override; published   // tests here end; The Setup and TearDown procedures are used to instantiate and dispose of an implementation of the IRatingCollector. const   SAMPLE_RATE_PROMPT = 'Rate DUnit (Mythological Slavic Feminine)';   SAMPLE_RATE_CHOICES: array[0..3] of string = ('Lada', 'Jurata', 'Marzanna', 'Baba Jaga'); procedure TRateTests.Setup; begin   // modify this line only to test another implementation of IRatingCollector   FRateCollector := TSimpleRatingCollector.Create(SAMPLE_RATE_PROMPT, SAMPLE_RATE_CHOICES); end; procedure TRateTests.TearDown; begin   FRateCollector := nil; end; Procedures declared in the published section are basic testing units; writing them requires inventiveness and creativity. In our example, TestChoices checks if the list of choices is as expected. procedure TRateTests.TestChoices; var   I: integer; begin   Check(FRatingCollector.GetChoiceCount = Length(SAMPLE_RATE_CHOICES),      Format('There should be exactly %d choices',         Length(SAMPLE_RATE_CHOICES)]));   for I := 0 to FRatingCollector.GetChoiceCount - 1 do     Check(FRatingCollector.GetChoice(I) = SAMPLE_RATE_CHOICES[I],           'Expected ' + SAMPLE_RATE_CHOICES[I]); end; The TestRate procedure checks if executing the Rate procedure results in increasing the number of rates for the rated choice: Procedure TestRate ...   FRatingCollector.Rate(NextRater, 0);   Check(FRatingCollector.GetRatingCount = RatingCount + 1,       'Expected ' + IntToStr(RatingCount + 1)); ... end; Tests should be as comprehensive as possible, but it's very difficult to cover all possible scenarios. While bugs are being reported, tests should be revised. It's very important that tests cover for extreme conditions; in our example, the choice or the rater passed to the Rate procedure might be invalid. The tests check if an exception is raised when an exception is expected. The following code checks if EinvalidRater exception is raised when a rater tries to rate second time. ErrorAsExpected := false; Rater := NextRater; try   FRatingCollector.Rate(Rater, 0);   FRatingCollector.Rate(Rater, 0); except   // exception expected   on E:EInvalidRater do     ErrorAsExpected := true; end; Check(ErrorAsExpected, 'Exception expected if a rater has already rated'); Finally, the registration of the test in the initialization section: RegisterTest('Basic tests', [TRateTests.Suite]); The project file shows the typical way to run tests in GUI mode. GUITestRunner.runRegisteredTests; To use CLX rather than the VCL, replace GUITestRunner with QGUITestRunner in qualified calls to runRegisteredTests as well as in the uses clause. Extreme cross-platform programming When porting DUnit to Kylix, there are two categories of problems, the difference between Windows and Linux system calls and the differences between VCL and CLX. Surprisingly, covering OS differences is easier. The first step is to put conditional statements in the uses clauses, units like Windows or Messages are of course not available in Kylix; prototypes of basic system calls can be found in the libc unit and basic type definitions in the Types and Qt standard units. Some system functions have been replaced by Linux equivalents, others have to be implemented. It took a number of tricks to port to CLX. CLX and VCL visual components are only slightly different, but despite this, sometimes porting can be quite difficult. DUnit for Delphi and Kylix compiles from the same source with the exception of GUITestRunner/QGUITestRunner GUI test runners, there are however a lot of conditional statements in the source to enable this cross platform support. This is just the beginning Once the basics have been mastered, there are many additional features within DUnit which enable more complex tests to be performed. For example, there are ready-made classes which can be used for a specific purpose, such as testing for a memory leak. The TestExtension unit contains a number of useful classes based on the Decorator design pattern. One of the most important is TRepeatedTest class, which allows you to execute a test case a given number of times. In this example, TRepeatedTest is used to call the Rate procedure several times in succession. RegisterTest('Repeated Rate',   TRepeatedTest.Create(TRateTests.Create('CheckRate'), 5)); The class TGUITestCase, supports testing of the GUI interface. TGUITestCase is declared in the GUITesting unit. See RateGUITests unit for an example of using it to test the dialog box to submit the rating. As the Delphi source for DUnit is freely available, so an experienced Delphi developer can easily extend DUnit, for example by creating new extensions. Testing as a liberated art Testing brings better results if tests are based on knowledge of the application design. If UML diagrams have been created, they can be used as a basis for the construction of tests, thus completing the requirement, analysis, implementation, testing cycle. Ideally, tests should be developed at the same time as the development of project code. Technically, tests can be created for applications which are already complete, however, these applications are often not suitable for unit testing since they don't have a well-developed modular structure. Using automated testing with DUnit promotes better application design as well as making it easier to refactor code, but I think the biggest difference it makes is at the stage of application maintenance. Maintainers can be assigned to units (in the sense of modules) rather than complete projects and they can bug fix and test units without building and testing a whole application. Sometimes a problem can be solved at the unit level and involvement of an experienced developer is necessary, but in the case of a large amorphic application, experienced developers have to be involved all the time.

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