Could someone point me to a version of CppUnit that would allow to launch the tests in separate threads?
The idea is that, because many of our tests are quite CPU heavy (but are not multi-thread and, of course, are independant one from the other), it would allow us to run the tests much more quickly on today's multi-core machines. Currently, it takes around 5 minutes to run all the tests. It would be great to be able to reduce this to 1 or 2 minutes...
You think five minutes is a long time to wait for tests to complete! Try several hours. I had motivation for the following.
Using Boost threads, CppUnit threading is pretty easy. CppUnit already has some hooks for synchronization so the following should make it thread safe:
class Mutex : public CPPUNIT_NS::SynchronizedObject::SynchronizationObject
{
public:
void lock() { this->mutex->lock(); }
void unlock() { this->mutex->unlock(); }
private:
boost::mutex mutex;
};
With this, you can modify your test runner to make your TestResult thread safe. Just write something like CPPUNIT_NS::TestResult testResult(new Mutex);. Now here's a threaded test suite:
class TestSuiteThreaded : public CPPUNIT_NS::TestSuite
{
public:
TestSuiteThreaded(std::string name = "", int nThreads = 0)
: TestSuite(name)
, nThreads(nThreads ? nThreads : boost::thread::hardware_concurrency())
{
}
void doRunChildTests(CPPUNIT_NS::TestResult *controller)
{
ThreadPool pool(this->nThreads);
for (int i=0; i < getChildTestCount(); ++i)
{
pool.add(
boost::bind(threadFunction, getChildTestAt(i)
, controller));
}
}
private:
static void threadFunction(
CPPUNIT_NS::Test *test,
CPPUNIT_NS::TestResult *controller)
{
test->run(controller);
}
const int nThreads;
};
You may well need a macro for easy use of the threaded test suite. You should be able to use TestSuiteThreaded suite either as a top level suite or a suite comprising multiple methods of the same text fixture. Here's how you do the latter - put this in place of CPPUNIT_TEST_SUITE_END. Some of this is pasted from CppUnit so please respect the license:
#define CPPUNIT_TEST_SUITE_END_THREADED(n) \
} \
static CPPUNIT_NS::TestSuite *suite() \
{ \
const CPPUNIT_NS::TestNamer &namer = getTestNamer__(); \
std::auto_ptr<CPPUNIT_NS::TestSuite> suite( \
new CPPUNIT_NS::TestSuiteThreaded( namer.getFixtureName(), n)); \
CPPUNIT_NS::ConcretTestFixtureFactory<TestFixtureType> factory; \
CPPUNIT_NS::TestSuiteBuilderContextBase context( *suite.get(), \
namer, \
factory ); \
TestFixtureType::addTestsToSuite( context ); \
return suite.release(); \
} \
private: /* dummy typedef so that the macro can still end with ';'*/ \
typedef int CppUnitDummyTypedefForSemiColonEnding__
Now there is the small matter of a ThreadPool. I tried using various publicly available ones with no success. My company has one but I'm unable to publish it here. So roll your own - thread pools are pretty easy and fun to make, with help from Boost. Here is the interface expected by TestSuiteThreaded:
class ThreadPool
{
public:
// Create thread pool, launching n worker threads
ThreadPool(unsigned n);
// Join all worker threads and clean up
~ThreadPool();
// You can have add() do one of two things. Both will work:
// Either: push a new task to the back of the threadpool's work queue
// Or: block until a worker is free then assign task to that thread
void add(boost::function0<void> task);
};
I leave this as an exercise for the reader. Have fun!
Given how many answers to this question you've gotten, especially as compared with the number of upvotes, I doubt anybody has made a good multi-threaded unit testing framework, no matter how great an idea it is. This looks like a great opportunity for someone to make a name for themselves developing something inordinately useful.
