Unit Testing in xcode(Using GHUnit and OCMock) -

in xcode,i trying unit testing using ghunit , ocmock described here :

unit testing xcode

and set methods descibed here :

ghunittestcase

but got error in method

• (void)setupclass { }

when initialize viewcontroller object below :

#import <ghunitios/ghunit.h> #import <ocmock/ocmock.h> #import "rs_loginrsviewcontroller.h"  @interface samplelibtest : ghtestcase {   rs_loginrsviewcontroller * login; } @end  @implementation samplelibtest  // run before each test method - (void)setup { }  // run after each test method - (void)teardown { }  // run before tests run class - (void)setupclass {  ghtestlog(@"log test ghtestlog(...) test specific logging.");  login = [[rs_loginrsviewcontroller alloc]init]; }  // run before tests run class  - (void)teardownclass { }  // tests prefixed 'test' , contain no arguments , no return value  - (void)testa {  ghtestlog(@"log test ghtestlog(...) test specific logging.");  }   // override exceptions; default exceptions raised, causing test failure   - (void)failwithexception:(nsexception *)exception { }  @end 

but got error apple mach-o linker error :

undefined symbols architecture i386: "_objc_class_$_rs_loginrsviewcontroller", referenced from: objc-class-ref in sampletestcase.o ld: symbol(s) not found architecture i386 clang: error: linker command failed exit code 1 (use -v see invocation)

but when remove line

     login = [[rs_loginrsviewcontroller alloc]init]; 

from

- (void)setupclass 

method runs successfully.why getting error ? appreciated.

i resolved errors adding necessary files , frameworks , library build phases of project target of testing.