/*! \page cppunit_cookbook CppUnit CookbookHere is a short cookbook to help you get started.\section simple_test_case Simple Test CaseYou want to know whether your code is working. How do you do it? There are many ways. Stepping through a debugger or littering your code with stream output calls are two of the simpler ways, but they both have drawbacks.Stepping through your code is a good idea, but it is not automatic. You have to do it every time youmake changes. Streaming out text is also fine, but it makes code ugly and it generates far more information than you need most of the time.Tests in %CppUnit can be run automatically. They are easy to set up and once you have written them, they are always there to help you keep confidence in the quality of your code.To make a simple test, here is what you do:Subclass the \link CppUnit::TestCase TestCase \endlink class. Override the method \link CppUnit::TestCase::runTest() runTest()\endlink. When you want to check a value, call \link CPPUNIT_ASSERT() CPPUNIT_ASSERT(bool) \endlinkand pass in an expression that is true if the test succeeds. For example, to test the equality comparison for a Complex number class, write:\codeclass ComplexNumberTest : public CppUnit::TestCase { public:   ComplexNumberTest( std::string name ) : CppUnit::TestCase( name ) {}    void runTest() {    CPPUNIT_ASSERT( Complex (10, 1) == Complex (10, 1) );    CPPUNIT_ASSERT( !(Complex (1, 1) == Complex (2, 2)) );  }};\endcodeThat was a very simple test. Ordinarily, you'll have many little test cases that you'll want to run on the same set of objects. To do this, use a fixture.\section fixture FixtureA fixture is a known set of objects that serves as a base for a set of test cases. Fixtures come in very handy when you are testing as you develop. Let's try out this style of development and learn about fixtures along the away. Suppose that we are really developing a complex number class. Let's start by defining a empty class named Complex.\codeclass Complex {};\endcodeNow create an instance of ComplexNumberTest above, compile the code and see what happens. The first thing we notice is a few compiler errors. The test uses <tt>operator ==</tt>, but it is not defined. Let's fix that.\codebool operator==( const Complex &a, const Complex &b) {   return true; }\endcodeNow compile the test, and run it. This time it compiles but the test fails. We need a bit more to get an <tt>operator ==</tt>working correctly, so we revisit the code.\codeclass Complex {   friend bool operator ==(const Complex& a, const Complex& b);  double real, imaginary;public:  Complex( double r, double i = 0 )     : real(r)	, imaginary(i)   {  }};bool operator ==( const Complex &a, const Complex &b ){   return eq( a.real, b.real )  &&  eq( a.imaginary, b.imaginary ); }\endcodeIf we compile now and run our test it will pass. Now we are ready to add new operations and new tests. At this point a fixture would be handy. We would probably be better off when doing our tests if we decided to instantiate three or four complex numbers and reuse them across our tests. Here is how we do it:- Add member variables for each part of the   \link CppUnit::TestFixture fixture \endlink- Override \link CppUnit::TestFixture::setUp() setUp() \endlink  to initialize the variables- Override \link CppUnit::TestFixture::tearDown() tearDown() \endlink  to release any permanent resources you allocated in   \link CppUnit::TestFixture::setUp() setUp() \endlink\codeclass ComplexNumberTest : public CppUnit::TestFixture {private:  Complex *m_10_1, *m_1_1, *m_11_2;protected:  void setUp()  {    m_10_1 = new Complex( 10, 1 );    m_1_1 = new Complex( 1, 1 );    m_11_2 = new Complex( 11, 2 );    }  void tearDown()   {    delete m_10_1;    delete m_1_1;    delete m_11_2;  }};\endcodeOnce we have this fixture, we can add the complex addition test case any any others that we need over the course of our development.\section test_case Test CaseHow do you write and invoke individual tests using a fixture? There are two steps to this process:- Write the test case as a method in the fixture class- Create a TestCaller which runs that particular methodHere is our test case class with a few extra case methods:\codeclass ComplexNumberTest : public CppUnit::TestFixture  {private:  Complex *m_10_1, *m_1_1, *m_11_2;protected:  void setUp()  {    m_10_1 = new Complex( 10, 1 );    m_1_1 = new Complex( 1, 1 );    m_11_2 = new Complex( 11, 2 );    }  void tearDown()   {    delete m_10_1;    delete m_1_1;    delete m_11_2;  }  void testEquality()  {    CPPUNIT_ASSERT( *m_10_1 == *m_10_1 );    CPPUNIT_ASSERT( !(*m_10_1 == *m_11_2) );  }  void testAddition()  {    CPPUNIT_ASSERT( *m_10_1 + *m_1_1 == *m_11_2 );  }};\endcodeOne may create and run instances for each test case like this:\codeCppUnit::TestCaller<ComplexNumberTest> test( "testEquality",                                              &ComplexNumberTest::testEquality );CppUnit::TestResult result;test.run( &result );\endcodeThe second argument to the test caller constructor is the address of a method on ComplexNumberTest. When the test caller is run, that specific method will be run.  This is not a useful thing to do, however, as no diagnostics will be displayed.  One will normally use a \link ExecutingTest TestRunner \endlink (see below) to display the results.Once you have several tests, organize them into a suite.\section suite SuiteHow do you set up your tests so that you can run them all at once?%CppUnit provides a \link CppUnit::TestSuite TestSuite \endlink class that runs any number of TestCases together. We saw, above, how to run a single test case.To create a suite of two or more tests, you do the following:\codeCppUnit::TestSuite suite;CppUnit::TestResult result;suite.addTest( new CppUnit::TestCaller<ComplexNumberTest>(                       "testEquality",                        &ComplexNumberTest::testEquality ) );suite.addTest( new CppUnit::TestCaller<ComplexNumberTest>(                       "testAddition",                        &ComplexNumberTest::testAddition ) );suite.run( &result );\endcode         \link CppUnit::TestSuite TestSuites \endlink don't only have to contain callers for TestCases.  They can contain any object that implements the \link CppUnit::Test Test \endlink interface.For example, you can create a \link CppUnit::TestSuite TestSuite \endlink in your code andI can create one in mine, and we can run them together by creating a \link CppUnit::TestSuite TestSuite \endlink that contains both:\codeCppUnit::TestSuite suite;CppUnit::TestResult result;suite.addTest( ComplexNumberTest::suite() );suite.addTest( SurrealNumberTest::suite() );suite.run( &result );\endcode\section test_runner TestRunnerHow do you run your tests and collect their results?Once you have a test suite, you'll want to run it. %CppUnit provides tools to define the suite to be run and to display its results. You make your suite accessible to a \link ExecutingTest TestRunner \endlinkprogram with a static method <I>suite</I> that returns a test suite.For example, to make a ComplexNumberTest suite available to a \link ExecutingTest TestRunner \endlink, add the following code to ComplexNumberTest:\codepublic:   static CppUnit::Test *suite()  {    CppUnit::TestSuite *suiteOfTests = new CppUnit::TestSuite( "ComplexNumberTest" );    suiteOfTests->addTest( new CppUnit::TestCaller<ComplexNumberTest>(                                    "testEquality",                                    &ComplexNumberTest::testEquality ) );    suiteOfTests->addTest( new CppUnit::TestCaller<ComplexNumberTest>(                                   "testAddition",                                   &ComplexNumberTest::testAddition ) );    return suiteOfTests;  }\endcode\anchor test_runner_codeTo use the text version, include the header files for the tests in Main.cpp:\code#include <cppunit/ui/text/TestRunner.h>#include "ExampleTestCase.h"#include "ComplexNumberTest.h"\endcodeAnd add a call to \link ::CppUnit::TextUi::TestRunner::addTest addTest(CppUnit::Test *) \endlink in the <tt>main()</tt> function:\codeint main( int argc, char **argv){  CppUnit::TextUi::TestRunner runner;  runner.addTest( ExampleTestCase::suite() );  runner.addTest( ComplexNumberTest::suite() );  runner.run();  return 0;}\endcodeThe \link ExecutingTest TestRunner \endlink will run the tests. If all the tests pass, you'll get an informative message. If any fail, you'll get the following information:- The name of the test case that failed- The name of the source file that contains the test- The line number where the failure occurred- All of the text inside the call to CPPUNIT_ASSERT() which detected the failure%CppUnit distinguishes between <I>failures</I> and <I>errors</I>. A failure is anticipated and checked for with assertions. Errors are unanticipated problems like division by zero and other exceptions thrown by the C++ runtime or your code.\section helper_macros Helper MacrosAs you might have noticed, implementing the fixture static <tt>suite()</tt> method is a repetitive and error prone task. A \ref WritingTestFixture set of macros have been created to automatically implements the static <tt>suite()</tt> method.The following code is a rewrite of ComplexNumberTest using those macros:\code#include <cppunit/extensions/HelperMacros.h>class ComplexNumberTest : public CppUnit::TestFixture  {\endcodeFirst, we declare the suite, passing the class name to the macro:\codeCPPUNIT_TEST_SUITE( ComplexNumberTest );\endcodeThe suite created by the static <tt>suite()</tt> method is named after the class name.Then, we declare each test case of the fixture:\codeCPPUNIT_TEST( testEquality );CPPUNIT_TEST( testAddition );\endcodeFinally, we end the suite declaration:\codeCPPUNIT_TEST_SUITE_END();\endcodeAt this point, a method with the following signature has been implemented:\codestatic CppUnit::TestSuite *suite();\endcodeThe rest of the fixture is left unchanged:\codeprivate:  Complex *m_10_1, *m_1_1, *m_11_2;protected:  void setUp()  {    m_10_1 = new Complex( 10, 1 );    m_1_1 = new Complex( 1, 1 );    m_11_2 = new Complex( 11, 2 );    }  void tearDown()   {    delete m_10_1;    delete m_1_1;    delete m_11_2;  }  void testEquality()  {    CPPUNIT_ASSERT( *m_10_1 == *m_10_1 );    CPPUNIT_ASSERT( !(*m_10_1 == *m_11_2) );  }  void testAddition()  {    CPPUNIT_ASSERT( *m_10_1 + *m_1_1 == *m_11_2 );  }};\endcodeThe name of the \link CppUnit::TestCaller TestCaller \endlink added to thesuite are a composition of the fixture name and the method name. In the present case, the names would be:"ComplexNumberTest.testEquality" and "ComplexNumberTest.testAddition".The \link WritingTestFixture helper macros \endlink help you write comon assertion.For example, to check that ComplexNumber throws a MathException when dividinga number by 0:- add the test to the suite using CPPUNIT_TEST_EXCEPTION, specifying the expected  exception type.- write the test case method\codeCPPUNIT_TEST_SUITE( ComplexNumberTest );// [...]CPPUNIT_TEST_EXCEPTION( testDivideByZeroThrows, MathException );CPPUNIT_TEST_SUITE_END();// [...]  void testDivideByZeroThrows()  {    // The following line should throw a MathException.    *m_10_1 / ComplexNumber(0);  }\endcodeIf the expected exception is not thrown, then a assertion failure is reported.\section test_factory_registry TestFactoryRegistryThe TestFactoryRegistry was created to solve two pitfalls:- forgetting to add your fixture suite to the test runner (since it is in   another file, it is easy to forget)- compilation bottleneck caused by the inclusion of all test case headers   (see \ref test_runner_code "previous example")The TestFactoryRegistry is a place where suites can be registered at initializationtime.To register the ComplexNumber suite, in the .cpp file, you add:\code#include <cppunit/extensions/HelperMacros.h>CPPUNIT_TEST_SUITE_REGISTRATION( ComplexNumber );\endcodeBehind the scene, a static variable type of \link CppUnit::AutoRegisterSuite AutoRegisterSuite \endlink is declared.On construction, it will \link CppUnit::TestFactoryRegistry::registerFactory(TestFactory*) register \endlink a \link CppUnit::TestSuiteFactory TestSuiteFactory \endlink into the \link CppUnit::TestFactoryRegistry TestFactoryRegistry \endlink. The \link CppUnit::TestSuiteFactory TestSuiteFactory \endlink returnsthe \link CppUnit::TestSuite TestSuite \endlink returned by ComplexNumber::suite().To run the tests, using the text test runner, we don't need to include the fixtureanymore:\code#include <cppunit/extensions/TestFactoryRegistry.h>#include <cppunit/ui/text/TestRunner.h>int main( int argc, char **argv){  CppUnit::TextUi::TestRunner runner;\endcodeFirst, we retreive the instance of the \link CppUnit::TestFactoryRegistry TestFactoryRegistry \endlink:\code  CppUnit::TestFactoryRegistry &registry = CppUnit::TestFactoryRegistry::getRegistry();\endcodeThen, we obtain and add a new \link CppUnit::TestSuite TestSuite \endlink created by the  \link CppUnit::TestFactoryRegistry TestFactoryRegistry \endlink that contains all the test suite registered using CPPUNIT_TEST_SUITE_REGISTRATION().\code  runner.addTest( registry.makeTest() );  runner.run();  return 0;}\endcode\section post_build_check Post-build checkWell, now that we have our unit tests running, how about integrating unit testing to our build process ?To do that, the application must returns a value different than 0 to indicate thatthere was an error.\link CppUnit::TextUi::TestRunner::run() TestRunner::run() \endlink returns a boolean indicating if the run was successful.Updating our main programm, we obtains:\code#include <cppunit/extensions/TestFactoryRegistry.h>#include <cppunit/ui/text/TestRunner.h>int main( int argc, char **argv){  CppUnit::TextUi::TestRunner runner;  CppUnit::TestFactoryRegistry &registry = CppUnit::TestFactoryRegistry::getRegistry();  runner.addTest( registry.makeTest() );  bool wasSucessful = runner.run( "", false );  return wasSucessful;}\endcodeNow, you need to run your application after compilation.With Visual C++, this is done in <em>Project Settings/Post-Build step</em>, by adding the following command: <tt>$(TargetPath)</tt>. It is expanded to the application executable path. Look up the project <tt>examples/cppunittest/CppUnitTestMain.dsp</tt> whichuse that technic.Original version by Michael Feathers.Doxygen conversion and update by Baptiste Lepilleur.*/