Boost C++ Libraries

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Log output stream redirection

If you want to redirect the test log output stream into something different from the logger default output stream (usually std::cout, std::cerr or a file), use the following interface:

boost::unit_test::unit_test_log.set_stream( std::ostream& );

or for a particular log format:

boost::unit_test::unit_test_log.set_stream( boost::unit_test::output_format, std::ostream& );

	Tip
	See `boost::unit_test::unit_test_log_t::set_stream` and `boost::unit_test::output_format` for more details

You can reset the output stream at any time both during the test module initialization and from within test cases. There are no limitations on number of output stream resets neither.

	Warning
	If you redirect test log output stream from global fixture setup, you are required to reset it back to `std::cout` during teardown to prevent dangling references access

Example: Compile-time log output redirection

Code

#define BOOST_TEST_MODULE example
#include <boost/test/included/unit_test.hpp>
#include <fstream>

struct MyConfig {
  MyConfig() : test_log( "example.log" ) {
    boost::unit_test::unit_test_log.set_stream( test_log );
  }
  ~MyConfig() {
    boost::unit_test::unit_test_log.set_stream( std::cout );
  }
  std::ofstream test_log;
};

BOOST_TEST_GLOBAL_CONFIGURATION( MyConfig );

BOOST_AUTO_TEST_CASE( test_case ) {
  BOOST_TEST( false );
}

Output
> example *** 1 failures is detected in test suite "example" > cat example.log Running 1 test case... test.cpp(26): error in "test_case": check false failed