Re: Unit testing of expected failures -- what do you use?

"Alf P. Steinbach" <>
Wed, 03 Mar 2010 20:13:54 +0100
* Carlo Milanesi:

Alf P. Steinbach wrote:

E.g., the problem isn't to produce compile time asserts. The problem
is testing them, systematically. Preferably in an automated way.

I published the following article that addresses specifically this
problem (after a tutorial on testing C++ programs):

I published also the open source utility described in that article.
It is in the files "staticpp.txt" and "" in the following

Hm, it's very similar to my approach. But instead of your @LEGAL and @ILLEGAL I
just use ordinary C++ preprocessor directives. This allows testing to be
performed manually, without any preprocessing or having a script at hand.

It also allows having just a single Visual C++ project and project settings for
the test suite for a library, and almost completely decouples the scripting side
from the C++ source code side.

The script -> C++ connection is that at the scripting side one defines the
relevant preprocessor macros for each test.

Before building a test the script places the macro definitions for the selected
test in a file '_config.h', which is the only C++ file that it knows about.

The Python test driver script (not exactly finished, but working!) is available
at <url:>.


The main program for my test suite for the lib I'm testing starts like this:

#include "_config.h" // Generated.

#if \
     defined( USE_STATIC_ASSERT ) || \
     defined( USE_STATIC_ASSERT__OVERRIDE ) || \
     defined( USE_DEBUGGER_API ) || \
     defined( USE_DEBUGGING ) || \
     defined( USE_FIXED_SIZE_TYPES ) || \
     defined( USE_TYPECHECKING ) || \
     // OK
# error Unknown test symbol or no test symbol defined.

I haven't gotten around to replace the "USE_" prefix with "TEST_" yet... :-)

A typical file to be tested (I just chose a short one):

// Copyright (c) Alf P. Steinbach, 2010.
#include <progrock/cppx/devsupport/static_assert.h>

#if \
     defined( CPPXTEST_NO_SUBTESTS ) || \
     defined( CERR_NONEXISTING ) || \
     // OK
# error Unknown or no subtest symbol defined (define CPPXTEST_NO_SUBTESTS?).

class Base
     virtual void foo( int, char const* ) const = 0;

class Derived:
     public Base
     virtual void foo( int a, char const* b ) const
         CPPX_IS_OVERRIDE_OF( Base::foo,(a, b) ); // Should compile fine.

     virtual void bar() const
         #if defined( CERR_NONEXISTING )
             CPPX_IS_OVERRIDE_OF( Base::bar,() ); // Should yield
compilation error.

Cheers, & thanks for that article ref!,

- Alf

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