Feature Request: BOOST_TEST_CONTEXT that doesn't require introducing a new scope with braces about test HOT 7 CLOSED

I may have better for you: making the context variadic, like this:

for (int i = 8; i < 24; ++i) {
    BOOST_TEST_CONTEXT("With level " << i, "Random value=" << some other value){

    }
}

Would that work for you? You can try it on the branch topic/GH-197-plural-context-in-single-scope

from test.

Unfortunately that doesn't actually do what I want it to. I need to build the context up as I generate data I want included in it so I can debug test failures. What I'm doing is something like this:

std::vector<uint8_t> data = ...; // generate data
MY_BOOST_TEST_CONTEXT("data      = " << data);
session->SendData(data, ... /* packet header fields */);

// RequirePacket() reads the data from the stream including the length header.
// It also does a few other checks to make sure the data isn't garbage.
const std::vector<uint32_t> packet = RequirePacket(numWords);
MY_BOOST_TEST_CONTEXT("packet    = " << packet);
// ... Do some other checks on the packet. ...
WriteSingleWord(TESTING_ACK); // Acknowledge the packet.

std::vector<uint8_t> parseData;
// ParsePacket() returns false if the packet was badly formatted or failed integrity checks.
BOOST_TEST(ParsePacket(packet, parseData, ... /* output parameters to receive header fields */));
MY_BOOST_TEST_CONTEXT("parseData = " << parseData);

// With all of the above context I can manually inspect the original data, sent packet, and parsed
// data in case this comparison fails.
BOOST_TEST(data == parseData, boost::test_tools::per_element());

I also use it to remove an extra level of indentation from the entire body of Require*() functions (like RequirePacket() above) like so:

#define RequirePacket(numWords) \
    Internal_RequirePacket((numWords), BOOST_TEST_L(__FILE__), static_cast<std::size_t>(__LINE__))
std::vector<uint32_t>
Internal_RequirePacket(unsigned numWords, boost::unit_test::const_string file, std::size_t line) {
    MY_BOOST_TEST_CONTEXT("RequirePacket() call-site: " << file << "(" << line << ")");

    // Code to read packet from stream and validate length and some other things.
    ...
}

from test.

I guess you have considered the assertion bound context ?

If a context needs to span several assertions, we need a scope, otherwise it will confuse users. If a context is associated to only one assertion, then BOOST_TEST_INFO is doing just fine.

What I did here is to have several information going into a single BOOST_TEST_CONTEXT, to avoid precisely having several scopes for a single context.

from test.

Yes. I need the context to span several assertions. I understand why you made BOOST_TEST_CONTEXT create a scope that the context will apply to. However, in my case I want the context to last for the rest of the enclosing scope. Is your last statement supposed to mean that adding context to the enclosing scope is an explicit non-goal?

from test.

It is not an explicit non-goal, but I need to think about it.

from test.

Ok, I implemented this via a new macro BOOST_TEST_INFO_SCOPE. Example of use

  for(int i = 0; i < 50; i++) {
    BOOST_TEST_INFO_SCOPE("trial " << i+1);
    int root1 = dis(gen);
    int root2 = dis(gen);
    if(root1 > root2) {
      std::swap(root1, root2);
    }
    BOOST_TEST_INFO_SCOPE("root1 = " << root1);
    BOOST_TEST_INFO_SCOPE("root2 = " << root2);

    std::pair<double, double> estimated = estimate_polynomial_roots(
      gen,
      [root1, root2](double x) -> double { return (x - root1) * (x - root2); });

    BOOST_TEST(estimated.first == double(root1), 10. % boost::test_tools::tolerance());
    BOOST_TEST(estimated.second == double(root2), 10. % boost::test_tools::tolerance());
  }

Let me know if that corresponds to what you asked (same branch as before if you want to give a try).

from test.

That fix does the trick. I'll work on getting everyone here using an upgraded or patched version. Thanks!

from test.