Referring the constant in test implementation file from controller implementation file

Question

I have few constants in my implementation file as below:

static const NSInteger kBookSectionCount = 3;
static const NSInteger kBookPopoverHeight = 400;
static NSString *kBookValue = @"Test Value";

I want to refer these constants in my test implementation file. Can I do it? I tried as below:

extern const NSInteger kBookSectionCount;
extern const NSInteger kBookPopoverHeight;
extern NSString *kBookValue;

I am getting the following error when I try the above way:

Undefined symbols for architecture i386:
  "_kBookSectionCount", referenced from:
      -[myClassTest testNumberOfSections] in myClass.o

Am I missing something here?