source: src/unittests/SingletonTest.cpp@ 88b400

/*
 * SingletonTest.cpp
 *
 *  Created on: Mar 11, 2010
 *      Author: crueger
 */

#include "SingletonTest.hpp"

#include <cppunit/CompilerOutputter.h>
#include <cppunit/extensions/TestFactoryRegistry.h>
#include <cppunit/ui/text/TestRunner.h>
#include <iostream>

#include "Patterns/Singleton.hpp"
#include "Patterns/Singleton_impl.hpp"

#ifdef HAVE_TESTRUNNER
#include "UnitTestMain.hpp"
#endif /*HAVE_TESTRUNNER*/

CPPUNIT_TEST_SUITE_REGISTRATION( SingletonTest );

// some necessary stubs
class SingletonStub1 : public Singleton <SingletonStub1>{
  friend class Singleton<SingletonStub1>;
private:
  SingletonStub1(){
    count1++;
  }
  // explicit copy constructor to catch if this is ever called
  SingletonStub1(const SingletonStub1&){
    CPPUNIT_FAIL    ( "Copy constructor of Singleton called" );
  }
  virtual ~SingletonStub1(){
    count2++;
  }
public:
  static int count1;
  static int count2;
};

int SingletonStub1::count1 = 0;
int SingletonStub1::count2 = 0;

CONSTRUCT_SINGLETON(SingletonStub1);

class SingletonStub2 : public Singleton<SingletonStub2>{
  friend class Singleton<SingletonStub2>;
private:
  SingletonStub2(){
    count1++;
  }
  // explicit copy constructor to catch if this is ever called
  SingletonStub2(const SingletonStub2&){
    CPPUNIT_FAIL    ( "Copy constructor of Singleton called" );
  }
  virtual ~SingletonStub2(){
    count2++;
  }
public:
  static int count1;
  static int count2;
};

int SingletonStub2::count1 = 0;
int SingletonStub2::count2 = 0;

CONSTRUCT_SINGLETON(SingletonStub2);

void SingletonTest::setUp(){}
void SingletonTest::tearDown(){}

void SingletonTest::ConstructionTest(){
  void *ptr_1_1 = reinterpret_cast<void*>(SingletonStub1::getPointer());
  void *ptr_1_2 = reinterpret_cast<void*>(SingletonStub1::getPointer());
  void *ptr_1_3 = reinterpret_cast<void*>(&(SingletonStub1::getInstance()));

  // test if we always get the same instance of our singleton
  CPPUNIT_ASSERT_EQUAL(ptr_1_1,ptr_1_2);
  CPPUNIT_ASSERT_EQUAL(ptr_1_1,ptr_1_3);

  void *ptr_2_1 = reinterpret_cast<void*>(SingletonStub2::getPointer());
  void *ptr_2_2 = reinterpret_cast<void*>(SingletonStub2::getPointer());
  void *ptr_2_3 = reinterpret_cast<void*>(&(SingletonStub2::getInstance()));

  // same as above but for a different singleton
  CPPUNIT_ASSERT_EQUAL(ptr_2_1,ptr_2_2);
  CPPUNIT_ASSERT_EQUAL(ptr_2_1,ptr_2_3);

  // see if the two singletons actually differ
  CPPUNIT_ASSERT(ptr_1_1!=ptr_2_1);

  // see if each constructor was called exactly once
  CPPUNIT_ASSERT_EQUAL(1,SingletonStub1::count1);
  CPPUNIT_ASSERT_EQUAL(1,SingletonStub2::count1);
  // no calls to the destructor should have occured so far
  CPPUNIT_ASSERT_EQUAL(0,SingletonStub1::count2);
  CPPUNIT_ASSERT_EQUAL(0,SingletonStub2::count2);

  SingletonStub1::purgeInstance();

  void *ptr_3_1 = reinterpret_cast<void*>(SingletonStub1::getPointer());
  void *ptr_3_2 = reinterpret_cast<void*>(SingletonStub1::getPointer());

  // now the constructor should have been called twice
  CPPUNIT_ASSERT_EQUAL(2,SingletonStub1::count1);
  // the destructor should have been called once
  CPPUNIT_ASSERT_EQUAL(1,SingletonStub1::count2);
  // see if the singleton Assumption holds
  CPPUNIT_ASSERT_EQUAL(ptr_3_1,ptr_3_2);
  // Some esoteric thing might cause our pointer to lay at the position of Singleton2 now
  // See that those two objects still differ
  CPPUNIT_ASSERT(ptr_3_1!=ptr_2_1);
  // don't test for pointer difference between first and second singleton here,
  // because they might be constructed in the same place


  SingletonStub2::resetInstance();
  // now the constructor should have been called twice
  CPPUNIT_ASSERT_EQUAL(2,SingletonStub2::count1);
  // the destructor should have been called once
  CPPUNIT_ASSERT_EQUAL(1,SingletonStub2::count2);

  void *ptr_4_1 = reinterpret_cast<void*>(SingletonStub2::getPointer());
  void *ptr_4_2 = reinterpret_cast<void*>(SingletonStub2::getPointer());

  // Still only two calls to the constructor, one call to destructor
  CPPUNIT_ASSERT_EQUAL(2,SingletonStub2::count1);
  CPPUNIT_ASSERT_EQUAL(1,SingletonStub2::count2);

  // test if Singleton assumption can be broken by reset
  CPPUNIT_ASSERT_EQUAL(ptr_4_1,ptr_4_2);

  // and again test if we actually have a object seperate from anything else
  CPPUNIT_ASSERT(ptr_4_1!=ptr_3_1);


  // we don't purge our singletons here. Purging should be done automatically by the Singleton
  // mechanism. Check with Valgrind to see if memory-leak occurs
  std::cout << "Not purging Singleton!\n Check with Valgrind to see if automatic purgins is working!" << std::endl;

}