Boost C++ Libraries

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Bitwise comparison

	Caution
	this feature is not available for non C++11 compilers.

The manipulator boost::test_tools::bitwise can be provided to the BOOST_TEST macro in order to have a bitwise comparison of the operands. In that case, the Unit Test Framework indicates the bit indices where the two operands do not match.

Example: BOOST_TEST bitwise comparison

Code

#define BOOST_TEST_MODULE boost_test_bitwise
#include <boost/test/included/unit_test.hpp>
#include <sstream>

BOOST_AUTO_TEST_CASE(test_bitwise)
{
  namespace tt = boost::test_tools;
  int a = 0xAB;
  BOOST_TEST( a == (a & ~1), tt::bitwise() );
  BOOST_TEST( a == a + 1, tt::bitwise() );
  BOOST_TEST( a != a + 1, tt::bitwise() );
  int b = 0x88;
  BOOST_TEST( a == b, tt::bitwise() );
}

Output

> ./boost_test_bitwise --log_level=all
Running 1 test case...
Entering test module "boost_test_bitwise"
test.cpp(13): Entering test case "test_bitwise"
test.cpp(17): error: in "test_bitwise": check a == (a & ~1) has failed [171 != 170]. Bitwise comparison failed
Mismatch at position 0
test.cpp(18): error: in "test_bitwise": check a == a + 1 has failed [171 != 172]. Bitwise comparison failed
Mismatch at position 0
Mismatch at position 1
Mismatch at position 2
test.cpp(19): info: check a != a + 1 has passed
test.cpp(21): error: in "test_bitwise": check a == b has failed [171 != 136]. Bitwise comparison failed
Mismatch at position 0
Mismatch at position 1
Mismatch at position 5
test.cpp(13): Leaving test case "test_bitwise"; testing time: 627us
Leaving test module "boost_test_bitwise"; testing time: 772us

*** 3 failures are detected in the test module "boost_test_bitwise"

	Note
	the indices start at least significant bit.