1. Create a projectwith ticking “include unit test” option inxcode.
* 生成的project會創建 2target, one for product app, one for unit test.
* For existingproject, to add unit test feature, just add a “unit testing bundle” type target
* By default, thereare 2 groups, one for product app, one for unit test. Unit test group裏的.mfiles的property panel都是指向 unit test target。 而在product app group裏的.mfiles都是指向product app target。不過2個group裏的.hfiles都不指向任何target。有文章說對要被unit test的需要同時指向2個target，但我試了一下，好像不需要。
2. 先說requirement，要創建一個class叫Calculator, 會包含一個加法的method。
3. TDD，先寫unittest:
* right click the unit testgroup, select “New File > Cocoa touch > objective c test case class”,click “next”
* set “Class” as “CalculatorTests”,click “Next”
* make sure unit test target is ticked, group is unit test, andfile path in unit test folder
* 代碼如下
//CalculatorTests.h
#import<SenTestingKit/SenTestingKit.h>
@class Calculator;
@interface CalculatorTests : SenTestCase{
Calculator* calculator;
}
@end
//CalculatorTests.m
#import"CalculatorTests.h"
#import"Calculator.h"
@implementation CalculatorTests
-(void) setUp{
calculator = [[Calculator alloc] init];
}
-(void) tearDown{
calculator = nil;
}
@end
4. 上面代碼編譯錯誤，因爲沒有Calculatorclass存在。現在創建一個classnamed “Calculator”，記住target指向product app target。
5. 繼續TDD, 添加下面測試加法method的代碼 in CalculatorTest.m
-(void) testAdd {
STAssertEquals([calculator add: 2to:3], 5, @"2 + 3 result should be5");
}
6. 編譯錯誤，因爲Calculator裏沒有add:to: method. 添加下列代碼
-(int) add: (int)a to: (int)b{
return a + b;
}
7. 這時運行”Test”,如果failed, error list就會出現在左邊的panel