delphi:Delphi中用TDD :一个简单的实现疯狂代码！

最近因工作

关系又再次搞了

些时候

Delphi开发

Java

影响也就开始思想如何在Delphi开发中用TDD

思路方法

这篇文章就是要谈谈TDD在Delphi中

应用

我想网上已有很多

文章谈到这方面

话题

我这篇也只是谈谈我自己

经验而已

那从何说起呢？用个具体

例子会更好

介绍说明问题

试想我们想开个动物繁殖中心

不过我们现阶段还没有特定

动物

先把这中心搞起来再说

不过中心是离不开动物

我们就先定义个接口:

IAnimal=Interface
="alt">procedureMate;
procedureEat;
="alt">procedureGiveBirth;
End;

这个接口定义了每种动物

3个基本功能:Eat(吃), Mate(交配), GiveBirth(生产), 为了简单起见

我们只处理母

公

不在考虑的内

有了接口我们就可以定义繁殖中心:

TAnimalCare=="keyword">
="alt">="keyword">private
FIntf:IAnimal;
="alt">="keyword">public
="keyword">constructorCreate(AnIntf:IAnimal);
="alt">="keyword">procedureReproduction;
="keyword">end;
="alt">

TAnimalCare 是处理繁殖

个类

它需要依靠IAnimal才可以繁殖

不过它并没有锁定任何

动物

所以在建立时需要注人

个基于IAnimal

类

有了IAnimal, TAnimalCare 我们需要个测试Project来对它们进行测试

DUnit是Delphi

很好

单元测试工具

如你用

是Delphi 2007版

DUnit已经在里面

如用

是早些

版本

可在DUnit下载

安装

建立好Test Project后

我们可以加入下面

这个TestCase:

TestTAnimalCare=="keyword">(TTestCase)
="alt">strict="keyword">private
FAnimalCare:TAnimalCare;
="alt">="keyword">public
="keyword">procedureSetUp;override;
="alt">="keyword">procedureTearDown;override;
="keyword">published
="alt">="keyword">procedureTestReproduction;
="keyword">end;
="alt">

在SetUp这里

需要个基于IAnimal

类才可以

至到目前我们并没有定义

个

同时我们也不需要

我们还没有特定

动物

那么如何来满足这条件以便测试能进行下去呢？这里我们可以用到

种叫Mock

东西

在Delphi可用PascalMock, 大家可在这下载

安装后

我们就可以定义个TAnimalMock:

TAnimalMock=="keyword">(TMock,IAnimal)
="alt">="keyword">public
="keyword">procedureMate;
="alt">="keyword">procedureEat;
="keyword">procedureGiveBirth;
="alt">="keyword">end;
="alt">="keyword">procedureTestTAnimalCare="number">.SetUp;
="keyword">begin
="alt">FMock:=TAnimalMock="number">.Create;
FAnimalCare:=TAnimalCare="number">.

Create(FMock);
="alt">="keyword">end;

有了TAnimalMock我们已基本满足了编译

要求

可以通过编译

是可以开始TDD

时候了

让我们先完善TestReproduction, 先写些期望

然后ver

看有没有达到:

="keyword">procedureTestTAnimalCare="number">.TestReproduction;
="alt">="keyword">begin
="comment">//Expectations
="alt">FMock="number">.Expects(="">'Mate');
FMock="number">.Expects(="">'Eat');
="alt">FMock="number">.Expects(="">'GiveBirth');
="alt">FAnimalCare="number">.Reproduction;
FMock="number">.Very(="">'check');
="alt">
="keyword">end;

这些期望是很自然

交配(mate),营养(eat)是生产(GiveBirth)

必须条件

否则是无法繁殖

我们跑

下测试

失败:

TestReproduction:EMockVeryException
="alt">at$0049B30A
check
="alt">UnexpectedcalltoGiveBirth="tag"><="tag-name">--Don'tmatchexpectations
="alt">Expected:
Mate
="alt">Eat
GiveBirth
="alt">
Called:
="alt">GiveBirth="tag"><="tag-name">--Don'tmatchexpectations

为什么？看看:

="keyword">procedureTAnimalCare="number">.Reproduction;
="alt">="keyword">begin
Ff="number">.GiveBirth;
="alt">="keyword">end;

原来我们只

GiveBirth而没

Mate

, Eat

, 不合我们

期望

改成如下:

="keyword">procedureTAnimalCare="number">.Reproduction;
="alt">="keyword">begin
FIntF="number">.Mate;
="alt">FIntF="number">.Eat;
Ff="number">.GiveBirth;
="alt">="keyword">end;

再跑下测试

成功！

整理总结:

用Dependency Injection 将基于IAnimal类注入TAnimalCare, 把有关IAnimal些具体实现从TAnimalCare中分离出来
用Mock来实现个基于IAnimal类以便测试.

IAnimal, TAnimalCare码如下:

="keyword">unitMyObjects;
="alt">
="keyword">erface
="alt">="keyword">uses
es;
="alt">
="keyword">type
="alt">IAnimal=Interface
="keyword">procedureMate;
="alt">

="keyword">procedureEat;
="keyword">procedureGiveBirth;
="alt">End;
="alt">TAnimalCare=="keyword">
="keyword">private
="alt">FIntf:IAnimal;
="keyword">public
="alt">="keyword">constructorCreate(AnIntf:IAnimal);
="keyword">procedureReproduction;
="alt">="keyword">end;
="alt">="keyword">implementation
="alt">="comment">{TAnimalCare}
="alt">="keyword">constructorTAnimalCare="number">.Create(AnIntf:IAnimal);
="keyword">begin
="alt">="keyword">inheritedCreate;
FF:=AnIntf;
="alt">="keyword">end;
="alt">="keyword">procedureTAnimalCare="number">.Reproduction;
="keyword">begin
="alt">FIntF="number">.Mate;
FIntF="number">.Eat;
="alt">Ff="number">.GiveBirth;
="keyword">end;
="alt">
="keyword">end.

测试码如下:

="keyword">unitTestMyObjects;
="alt">
="keyword">erface
="alt">
="keyword">uses
="alt">TestFramework,es,MyObjects,PascalMock;
="keyword">type
="alt">
TAnimalMock=="keyword">(TMock,IAnimal)
="alt">="keyword">public
="keyword">procedureMate;
="alt">="keyword">procedureEat;
="keyword">procedureGiveBirth;
="alt">="keyword">end;
="alt">TestTAnimalCare=="keyword">(TTestCase)
strict="keyword">private
="alt">FMock:TAnimalMock;
FAnimalCare:TAnimalCare;
="alt">="keyword">public
="keyword">procedureSetUp;override;
="alt">="keyword">procedureTearDown;override;
="keyword">published
="alt">="keyword">procedureTestReproduction;
="keyword">end;
="alt">
="keyword">implementation
="alt">
="keyword">procedureTestTAnimalCare="number">.SetUp;
="alt">="keyword">begin
FMock:=TAnimalMock="number">.Create;
="alt">FAnimalCare:=TAnimalCare="number">.Create(FMock);
="keyword">end;
="alt">
="keyword">procedureTestTAnimalCare="number">.TearDown;
="alt">="keyword">begin
FAnimalCare="number">.Free;
="alt">FAnimalCare:=="keyword">nil;
FMock="number">.Free;
="alt">FMock:=="keyword">nil;
="keyword">end;
="alt">
="keyword">procedureTestTAnimalCare="number">.TestReproduction;
="alt">="keyword">begin
="comment">//Expectations
="alt">FMock="number">.Expects(="">'Mate');
FMock="number">.Expects(="">'Eat');
="alt">FMock="number">.Expects(="">'GiveBirth');
="alt">FAnimalCare="number">.Reproduction;
FMock="number">.Very(="">'check');
="alt">
="keyword">end;
="alt">
="comment">{TAnimalMock}
="alt">
="keyword">procedureTAnimalMock="number">.Eat;
="alt">="keyword">begin
self="number">.AddCall(="">'Eat');
="alt">="keyword">end;
="alt">="keyword">procedureTAnimalMock="number">.GiveBirth;
="keyword">begin
="alt">self="number">.AddCall(="">'GiveBirth');
="keyword">end;
="alt">
="keyword">procedureTAnimalMock="number">.Mate;
="alt">="keyword">begin
self="number">.AddCall(="">'Mate');
="alt">="keyword">end;
="alt">="keyword">initialization
RegisterTest(TestTAnimalCare="number">.Suite);
="alt">="keyword">end.

delphi:Delphi中用TDD :一个简单的实现

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