Catch test framework issue: cannot use Catch::Session()

Question

I get this error in a C++ file where I am writing some tests:

error: no member named 'Session' in namespace 'Catch'
        testResult = Catch::Session().run(test_argc, test_argv);
                     ~~~~~~~^

Looking at the catch.hpp single header file, I noticed that the code that should implement the Session() member function is greyed out, probably because of an #ifdef somewhere, which I cannot find.

Is there any macro to set to use the Session class?

Catch versions: 1.5.3 and 1.5.6.

Reference: https://github.com/philsquared/Catch/blob/master/docs/own-main.md

obligatory sanity check: you *are* defining `CATCH_CONFIG_RUNNER` before you `#include` catch.hpp, right? — jaggedSpire, Jun 29 '16 at 17:00
@jaggedSpire - Yes, just once, in the file where I define main(), which is not the one where I write the tests. — Pietro, Jun 29 '16 at 17:14
and the compilation error is in the file where you define main(), correct? — jaggedSpire, Jun 29 '16 at 17:18
It doesn't look like you're supposed to call `Catch::Session()` outside of the file where you're defining your own main, or even construct it. The documentation explicitly says there should only ever be once instance of it: "`Catch::Session session; // There must be exactly once instance`" Presumably, preventing it from being defined in non-main files is meant to prevent violation of that requirement. — jaggedSpire, Jun 29 '16 at 17:33
You are right. I called it just once, but in a different file. Now it works. If you write it as an answer, I will accept it. Thank you! — Pietro, Jun 29 '16 at 17:39
Done. Would you mind editing your question to include the information about where you were attempting to access `Catch::Session`? — jaggedSpire, Jun 29 '16 at 17:46

score 4 · Accepted Answer · answered Jun 29 '16 at 17:45

4

You're attempting to call the constructor of Catch::Session from a file where you're not defining your own main to execute. According to the documentation on defining your own main, there is supposed to be only one instance of Catch::Session:

Catch::Session session; // There must be exactly once instance

It's likely Catch is preventing construction of Catch::Session in translation units where it can't be used in a custom main definition (since that's where it's supposed to be used), to prevent exactly the mistake you've made from compiling.

answered Jun 29 '16 at 17:45

jaggedSpire

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and what if I want to run tests multiple times per one application run, with different argc, how can ones do that, without using only one instance, that seems to be keeping arguments.. – Andrey Suvorov Jan 09 '18 at 22:38
sounds like new question material to me. – jaggedSpire Jan 09 '18 at 23:09

score 1 · Answer 2 · answered Sep 21 '20 at 12:12

Reference to https://github.com/catchorg/Catch2/blob/master/docs/own-main.md

You can only provide main in the same file you defined CATCH_CONFIG_RUNNER.

#define CATCH_CONFIG_RUNNER
#include "catch.hpp"

int main( int argc, char* argv[] ) {
  // global setup...

  int result = Catch::Session().run( argc, argv );

  // global clean-up...

  return result;
}

Catch test framework issue: cannot use Catch::Session()

2 Answers2