Unit Test Cpp

Since you're sane and understand AlternateHardAndSoftLayers as well as RefactoringWithCeePlusPlus, you may start thinking about how you'd unit test C++. The various incarnations of CppUnit are horribly bloated; you can go far farther with a lot less. Here's the deal:

 template < class TestFixture >
 void runTest
 (
	TestVisitor? &				testVisitor,
	char const * const			testName,
	void (TestFixture::*			testCase
	)(TestVisitor? &)
 )
 {
	try
	{
	TestFixture f;
	(f.*testCase)(testVisitor);

testVisitor.describe(testName); // streams the good/bad notification } catch(exception e) { testVisitor() << "EXCEPTION: " << e.what() << " in " << testName << endl; } catch(...) { testVisitor() << "EXCEPTION: unknown in " << testName << endl; } } #define RUN(arg) runTest(visitor, #arg, &arg)
 #define TEST(arg)	if (!(v &= (arg))) v() << " FAILED: " << #arg << endl;
As you can see, it's really not a big deal if you don't make some kind of LanguageLawyer fuss over it like on UnitTestingNonPublicMemberFunctions. Geesh.

I really like this page. I wish I had been smart enough to do this when I was doing C++. I think calling UnitTestingNonPublicMemberFunctions a "LanguageLawyer fuss" is a bit strong. To me, a LanguageLawyer fuss involves PartialTemplateInstantion?, not deciding whether or not to test private member functions. By the way, do you test private member functions? -- WayneConrad

What private member functions? I rely on soft language encapsulation and make all the C++ classes structs - all public to other C++, all private otherwise. Accessors, phooey.

Have you published anything with source that shows the AlternateHardAndSoftLayers pattern in action? -- WayneConrad

I haven't, and to tell the truth I'm still trying to formalize the concept of SoftLanguageEncapsulation?. But check out http://cxx.sourceforge.net for a very good place to start. --PeterMerel


Actually you should avoid names which begin with an underline, especially if it is followed by a capital. They are reserved for the implementation. Eg struct _Foo is not conforming C++; it invokes undefined behaviour.

Names ending with an underline are OK - eg struct Foo_. -- DaveHarris

Dig it. Will change it.
Why do you need the visitor? Why are you so against inheritance here?

It sounds like the test case will get linked into the final executable - do you use conditional compilation to avoid that? It seems you have to use the preprocessor a lot.

I don't see how this solves the problem of UnitTestingNonPublicMemberFunctions. The unit test doesn't get access to private member functions just because it is in the same compilation unit. -- DaveHarris

See comments on RefactoringWithCeePlusPlus.

I'm still trying to adsorb Peter's AlternateHardAndSoftLayers pattern, but I think it gets around the problem by not having any private member functions. -- WayneConrad

Are we saying we're not really writing in C++, but in some other language implemented on top of C++, so it doesn't matter that the C++ is badly structured? I don't think this is what people usually mean by C++ development. -- DaveHarris
CategoryTesting

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