Boost data-driven test output: "Assertion occurred in a following context"

Question

I have a question regarding the output of the following minimal example that uses Boost test.

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

#include <boost/test/unit_test.hpp>
using boost::unit_test::test_suite;
using boost::unit_test::framework::master_test_suite;

#include <boost/test/data/test_case.hpp>
namespace bdata = boost::unit_test::data;

BOOST_DATA_TEST_CASE(ExampleTest, bdata::xrange(2), testDatum) {

    int exp = testDatum == 0 ? 0 : 1;

    BOOST_CHECK_EQUAL(testDatum, exp);
}

If I run this test with ./boost_testing --log_level=all, I get the following output:

Running 2 test cases...
Entering test module "ExampleTestSuite"
boost_testing.cpp(11): Entering test suite "ExampleTest"
boost_testing.cpp(11): Entering test case "_0"
boost_testing.cpp(15): info: check testDatum == exp has passed
Assertion occurred in a following context:
    testDatum = 0;
boost_testing.cpp(11): Leaving test case "_0"
boost_testing.cpp(11): Entering test case "_1"
boost_testing.cpp(15): info: check testDatum == exp has passed
Assertion occurred in a following context:
    testDatum = 1;
boost_testing.cpp(11): Leaving test case "_1"
boost_testing.cpp(11): Leaving test suite "ExampleTest"
Leaving test module "ExampleTestSuite"

*** No errors detected

What is the meaning of the output line Assertion occurred in a following context: testDatum = 0;? Does it indicate an issue with the way that I have set up the data-driven test case or can I safely ignore it?

Answer 1

I agree the message is confusing: this is in fact the description of the assertion context for the test BOOST_CHECK_EQUAL(testDatum, exp), and in fact this is not describing an error, but the context attached to the check. If you change --log_level=all to something else, or user another output format, this should go away.

Feel free to raise an issue on Boost.Test project