Re: Testing for code that should not compile?

francis_r wrote:


But then Tester should actually repeat the work done so far by the
compiler, i.e. compile the Widget declaration with everything it
depends on.

Currently I use the following for this purpose:

#define DEBUGTOOLS_CONCAT(x,y) DEBUGTOOLS_CONCAT_(x,y)
#define DEBUGTOOLS_CONCAT_(x,y) x ## y

#define DEBUGTOOLS_COMPILER_ERROR( id ) \
  enum DEBUGTOOLS_CONCAT( __MsgEnum, __LINE__ ) \
    { DEBUGTOOLS_CONCAT( __MsgEnumVal, __LINE__ ) = 0x7fffffff, \
      DEBUGTOOLS_CONCAT( id, DEBUGTOOLS_CONCAT( _, __LINE__ ) ) };

#ifdef DEBUGTOOLS_TEST_NOCOMPILE
  #define TEST_NOCOMPILE( expr ) \
    DEBUGTOOLS_COMPILER_ERROR(
A_compilation_error_should_follow_on_this_line ) \
    expr
#else
  #define TEST_NOCOMPILE( expr ) ((void)0)
#endif

Then I use TEST_NOCOMPILE( somecode ) in my test cases, and when I work
on some component I enable DEBUGTOOLS_TEST_NOCOMPILE and check visually
if all file(line) messages in the compiler output are met (at least)
twice - the first is for the
A_compilation_error_should_follow_on_this_line deliberate error and the
second (or more) for the actual error.

It's a bit heavy and not automatic, but enough for me. Even if you
don't check with the compiler that the code really doesn't compile, the
TEST_NOCOMPILE macros serve as good documentation.

I suppose for a language like C++ which counts very much on catching
errors at compile-time, there should be appropriate test tools for that
(don't know at what level - the language, the compiler, the IDE, or
some other).

Regards,
Ivan

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