lest_expect_abort

Expect abort assertions

This extension lets you assert assertions and other calls to abort(). It works by substituting abort from the standard library with a version of our own and throwing an exception when abort is called [1].

There are two versions of this extension:

• lest_expect_abort.hpp - for C++11 and higher
• lest_expect_abort_cpp03.hpp - for C++98/03 and higher

Please note the following:

• In an executable that uses lest_expect_abort, you can no longer use abort for other purposes than testing, e.g. to enter a debugger.
• For C++11 and higher, throwing an abortion-occurred exception makes it impossible to verify assertions or calls to abort that live in or beneath functions that are specified as noexcept. If your code uses a macro to specify noexcept, you may be able to substitute nothing for it for the tests [2]. Otherwise this extension is of limited use with C++11 and higher.
• For Visual C++, if the abortion-occurred exception travels through a C function, the code must be compiled without the 'c' (extern "C" defaults to nothrow) in option -EHsc.

Dependencies

lest_expect_abort requires headers io.h and fcntl.h for suppression of messages from assert.

Assertion macros

lest_EXPECT_NO_ABORT( expr ) Evaluate the expression and expect that abort is not called. If abort() is called or if an exception (of any type) is thrown it reported and counted as a failure.

lest_EXPECT_ABORTS( expr ) Evaluate the expression and expect that abort is called. If abort() is not called or if an exception (of any type) is thrown it is reported and counted as a failure.

Example usage

#include "lest/lest_expect_abort.hpp"
#include <cassert>

#define CASE( name ) lest_CASE( specification, name )

static lest::tests specification;

CASE( "Expect_aborts succeeds for assert(false) " "[pass]" )
{
    EXPECT_ABORTS( assert( false ) );
}

int main( int argc, char * argv[] )
{
    return lest::run( specification, argc, argv /*, std::cout */ );
}

Compile and run

Using g++:

prompt>g++ -Wall -std=c++11 -Dlest_FEATURE_AUTO_REGISTER=1 -I.. -I../../../include -o 00_basic.exe 00_basic.cpp && 00_basic.exe --pass
00_basic.cpp:10: passed: aborted: Expect_aborts succeeds for assert(false) [pass]: assert( false )
All 1 selected test passed.

With VC14 (VS2015):

prompt>cl -EHsc -Dlest_FEATURE_AUTO_REGISTER=1 -I.. -I../../../include 00_basic.cpp && 00_basic.exe --pass
...
00_basic.cpp(15): passed: aborted: Expect_aborts succeeds for assert(false) [pass]: assert( false )
All 1 selected test passed.

Compiling with a pre-VC14 compiler requires linker option /FORCE:MULTIPLE to accept the multiply defined abort symbol.

prompt>cl -EHsc -Dlest_FEATURE_AUTO_REGISTER=1 -I.. -I../../../include 00_basic.cpp /link /FORCE:MULTIPLE && 00_basic.exe --pass
...
LIBCMT.lib(abort.obj) : warning LNK4006: _abort already defined in 00_basic.obj; second definition ignored
00_basic.exe : warning LNK4088: image being generated due to /FORCE option; image may not run
00_basic.cpp(10): passed: aborted: Expect_aborts succeeds for assert(false) [pass]: assert( false )
All 1 selected test passed.

Notes

[1] A previous version of this extension used setjmp() and longjmp() for flow control. However this mechanism doesn't mix well with C++ as it completely subverts stack unwinding and thus exception handling and object destruction.

[2] Visual C++ 14 (Visual Studio 2015) does not let you #define noexcept /*empty*/. Besides it would be hard to also hide noexcept expressions.

Appendix A: Test specification

Issuing command example\00-specification.exe -l @ gives the following listing of the test specification:

Expect_aborts succeeds for ::abort() [pass]
Expect_aborts succeeds for std::abort() [pass]
Expect_aborts succeeds for assert(false) [pass]
Expect_aborts reports assert(true) [fail]
Expect_asserts succeeds for assert(false) in non-noexcept function [pass]
Expect_aborts terminates for assert(false) in noexcept function [.pass]
Expect_aborts reports an unexpected standard exception [fail]
Expect_aborts reports an unexpected non-standard exception [fail]
Expect_no_abort succeeds for assert(true) [pass]
Expect_no_abort reports ::abort() [fail]
Expect_no_abort reports std::abort() [fail]
Expect_no_abort reports assert(false) [fail]
Expect_no_abort reports an unexpected standard exception [fail]
Expect_no_abort reports an unexpected non-standard exception [fail]