Читаем Thinking In C++. Volume 2: Practical Programming полностью

#include

using std::string;

using std::ostream;

using std::cout;

// The following have underscores because

// they are macros. For consistency,

// succeed_() also has an underscore.

#define test_(cond) \

  do_test(cond, #cond, __FILE__, __LINE__)

#define fail_(str) \

  do_fail(str, __FILE__, __LINE__)

namespace TestSuite {

class Test {

public:

  Test(ostream* osptr = &cout);

  virtual ~Test(){}

  virtual void run() = 0;

  long getNumPassed() const;

  long getNumFailed() const;

  const ostream* getStream() const;

  void setStream(ostream* osptr);

  void succeed_();

  long report() const;

  virtual void reset();

protected:

  void do_test(bool cond, const string& lbl,

    const char* fname, long lineno);

  void do_fail(const string& lbl,

    const char* fname, long lineno);

private:

  ostream* osptr;

  long nPass;

  long nFail;

  // Disallowed:

  Test(const Test&);

  Test& operator=(const Test&);

};

inline Test::Test(ostream* osptr) {

  this->osptr = osptr;

  nPass = nFail = 0;

}

inline long Test::getNumPassed() const {

  return nPass;

}

inline long Test::getNumFailed() const {

  return nFail;

}

inline const ostream* Test::getStream() const {

  return osptr;

}

inline void Test::setStream(ostream* osptr) {

  this->osptr = osptr;

}

inline void Test::succeed_() {

  ++nPass;

}

inline void Test::reset() {

  nPass = nFail = 0;

}

} // namespace TestSuite

#endif // TEST_H ///:~

There are three virtual functions in the Test class:

·         A virtual destructor

·         The function reset( )

·         The pure virtual function run( )

As explained in Volume 1, it is an error to delete a derived heap object through a base pointer unless the base class has a virtual destructor. Any class intended to be a base class (usually evidenced by the presence of at least one other virtual function) should have a virtual destructor. The default implementation of the Test::reset( ) resets the success and failure counters to zero. You might want to override this function to reset the state of the data in your derived test object; just be sure to call Test::reset( ) explicitly in your override so that the counters are reset. The Test::run( ) member function is pure virtual, of course, since you are required to override it in your derived class^.

The test_( ) and fail_( ) macros can include file name and line number information available from the preprocessor. We originally omitted the trailing underscores in the names, but the original fail( ) macro collided with ios::fail( ), causing all kinds of compiler errors^.

Here is the implementation of Test:

//: TestSuite:Test.cpp {O}

#include "Test.h"

#include

#include   // Note: Visual C++ requires /GR

using namespace std;

using namespace TestSuite;

void Test::do_test(bool cond,

  const std::string& lbl, const char* fname,

  long lineno) {

  if (!cond)

    do_fail(lbl, fname, lineno);

  else

    succeed_();

}

void Test::do_fail(const std::string& lbl,

  const char* fname, long lineno) {

  ++nFail;

  if (osptr) {

    *osptr << typeid(*this).name()

           << "failure: (" << lbl << ") , "

           << fname

           << " (line " << lineno << ")\n";

  }

}

long Test::report() const {

  if (osptr) {

    *osptr << "Test \"" << typeid(*this).name()

           << "\":\n\tPassed: " << nPass

           << "\tFailed: " << nFail

           << endl;

  }

  return nFail;

} ///:~

No rocket science here. The Test class just keeps track of the number of successes and failures as well as the stream where you want Test::report( ) to display the results. The test_( ) and fail_( ) macros extract the current file name and line number information from the preprocessor and pass the file name to do_test( ) and the line number to do_fail( ), which do the actual work of displaying a message and updating the appropriate counter. We can’t think of a good reason to allow copy and assignment of test objects, so we have disallowed these operations by making their prototypes private and omitting their respective function bodies^.

Here is the header file for Suite:^.

//: TestSuite:Suite.h

#ifndef SUITE_H

#define SUITE_H

#include "../TestSuite/Test.h"

#include

#include

using std::vector;

using std::logic_error;

namespace TestSuite {

class TestSuiteError : public logic_error {

public:

  TestSuiteError(const string& s = "")

    : logic_error(s) {}

};

class Suite {

public:

  Suite(const string& name, ostream* osptr = &cout);

  string getName() const;

  long getNumPassed() const;

  long getNumFailed() const;

  const ostream* getStream() const;

  void setStream(ostream* osptr);

  void addTest(Test* t) throw (TestSuiteError);

  void addSuite(const Suite&);

  void run();  // Calls Test::run() repeatedly

  long report() const;

  void free();  // Deletes tests

private:

  string name;

  ostream* osptr;

  vector tests;

  void reset();

  // Disallowed ops:

  Suite(const Suite&);

  Suite& operator=(const Suite&);

};

inline

Suite::Suite(const string& name, ostream* osptr)

   : name(name) {

  this->osptr = osptr;

}

inline string Suite::getName() const {

  return name;

}

inline const ostream* Suite::getStream() const {

  return osptr;

}

inline void Suite::setStream(ostream* osptr) {

  this->osptr = osptr;

}

} // namespace TestSuite