How to send custom message in Google C++ Testing Framework?

Question

I use Google C++ Testing Framework for unit testing of my code. I use Eclipse CDT with C++ Unit testing module for output analysis.

Previously I used CppUnit it has macros family CPPUNIT*_MESSAGE that could be called like this:

CPPUNIT_ASSERT_EQUAL_MESSAGE("message",EXPECTED_VALUE,ACTUAL_VALUE)

And allows to send custom messages to test output.

Is there a way to include some custom text in google test output?

(Preferably the way that could include message to data that is read by existing programs for automated unit testing using google test.)

score 221 · Accepted Answer · answered May 10 '13 at 22:50

221

The gtest macros return a stream for outputting diagnostic messages when a test fails.

EXPECT_TRUE(false) << "diagnostic message";

answered May 10 '13 at 22:50

user2093113

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@ErikAronesty Have you taken a look in the source to see if there's an easy-ish way to interface with that data? – kayleeFrye_onDeck Feb 06 '16 at 01:15
2

If you need to print the text regardless of the result, simply write it to stdout. But this usually results very noisy tests, difficult to work with. – Audrius Meškauskas Jul 11 '18 at 08:25
6

FAIL() << "diagnostic message"; works the same way, but it does reduce the generated output by a few lines as it does not tell you about actual value, expected value and so on, which it does for all EXPECT_X() macros. Just in case you want to reduce output length a little bit. – BallisticTomato Aug 03 '20 at 12:59
@BallisticTomato, that's the real answer right there. – Kenn Sebesta Oct 09 '21 at 17:22
Do you know where this is at in the documentation? – Gabriel Staples Dec 08 '21 at 17:46
I don't know where it explicitly says it, but if you search [this page](https://github.com/google/googletest/blob/main/docs/advanced.md) for `) <<` you'll at least see a variety of examples of this feature. – Gabriel Staples Dec 08 '21 at 17:48
1

Take a look at [SCOPED_TRACE](https://stackoverflow.com/a/71349117/8366223) as well – PolyGlot Mar 04 '22 at 09:20

Mark Lakata · Answer 2 · 2016-06-09T17:39:13.397

There is no way of doing it cleanly in the current version of gtest. I looked at the code, and the only text output (wrapped in gtest "Messages") is shown if you fail a test.

However, at some point, gtest starts printf'ing to the screen, and you can leverage the level above that to get colors that are platform independent.

Here's a hacked macro to do what you want. This uses the gtest internal text coloring. Of course the internal:: namespace should be sounding off warning bells, but hey, it works.

Usage:

TEST(pa_acq,Foo)
{
  // C style
  PRINTF("Hello world \n");

  // or C++ style

  TEST_COUT << "Hello world" << std::endl;
}

Output:

Example output

Code:

namespace testing
{
 namespace internal
 {
  enum GTestColor {
      COLOR_DEFAULT,
      COLOR_RED,
      COLOR_GREEN,
      COLOR_YELLOW
  };

  extern void ColoredPrintf(GTestColor color, const char* fmt, ...);
 }
}
#define PRINTF(...)  do { testing::internal::ColoredPrintf(testing::internal::COLOR_GREEN, "[          ] "); testing::internal::ColoredPrintf(testing::internal::COLOR_YELLOW, __VA_ARGS__); } while(0)

// C++ stream interface
class TestCout : public std::stringstream
{
public:
    ~TestCout()
    {
        PRINTF("%s",str().c_str());
    }
};

#define TEST_COUT  TestCout()

Thanks, this is the correct solution, IMHO. But can I suggest to add a `\n` in the PRINTF inside the class? that's because we cannot join lines with TEST_COUT as we do with `std::cout`, so it is useless to let the user add his `\n`. Thank you anyway! — HappyCactus, Sep 01 '17 at 12:48
Unfortunately this approach doesn't work any longer with modern versions of Google Test - `testing::internal::ColoredPrintf` isn't available any longer to the public :( — AntonK, Jun 27 '20 at 19:57

Just Shadow · Answer 3 · 2021-06-16T18:55:09.203

35

There is a quite simple and hacky way for doing it (without the need of diving into internal classes or creating new custom classes).

Just define a macro:

#define GTEST_COUT std::cerr << "[          ] [ INFO ]"

and use GTEST_COUT (just like cout ) in your tests :

GTEST_COUT << "Hello World" << std::endl;

And you'll see the result:

Credit goes to @Martin Nowak for his finding.

edited Jun 16 '21 at 18:55

answered Feb 22 '18 at 10:13

Just Shadow

10,860
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Vlad · Answer 4 · 2021-05-14T14:11:07.873

14

From the Advanced googletest Topics you can use a few macros for that purpose.

SUCCEED() SUCCEED() << "success/info message"; SUCCEED() only outputs your message and proceeds. It does not mark test as passed. Its result will be determined by the following asserts.
FAIL() FAIL() << "test failure message"; FAIL() marks your test as failed, outputs your message and then returns from the function. Therefore can only be used in functions returning void.
ADD_FAILURE() ADD_FAILURE() << "test failure message"; ADD_FAILURE() marks your test as failed and outputs your message. It does not return from the calling function and execution flow continues like with EXPECT_ series of macros.

edited May 14 '21 at 14:11

answered Nov 24 '20 at 11:37

Vlad

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The link provided isn't alive anymore, but I found it here: https://google.github.io/googletest/advanced.html Also, the SUCCEED() macro explicitly doesn't print anything to the output at the moment, but they "may" add it in the future. – AberrantWolf May 13 '21 at 06:37
1

Best answer right here. – Kenn Sebesta Oct 09 '21 at 17:25

score 5 · Answer 5 · answered Jul 27 '17 at 08:11

Refer to Mark Lakata's answer, here is my way:

Step1: create a header file, for example: gtest_cout.h

Code:

#ifndef _GTEST_COUT_H_
#define _GTEST_COUT_H_

#include "gtest/gtest.h"

namespace testing
{
namespace internal
{
enum GTestColor
{
    COLOR_DEFAULT, COLOR_RED, COLOR_GREEN, COLOR_YELLOW
};
extern void ColoredPrintf(GTestColor color, const char* fmt, ...);
}
}

#define GOUT(STREAM) \
    do \
    { \
        std::stringstream ss; \
        ss << STREAM << std::endl; \
        testing::internal::ColoredPrintf(testing::internal::COLOR_GREEN, "[          ] "); \
        testing::internal::ColoredPrintf(testing::internal::COLOR_YELLOW, ss.str().c_str()); \
    } while (false); \

#endif /* _GTEST_COUT_H_ */

Step2: use GOUT in your gtest

Usage:

#include "gtest_cout.h"

TEST(xxx, yyy)
{
    GOUT("Hello world!");
}

ColoredPrintf has been made static in a recent version, so this hack will not work any more. — schwart, Aug 21 '19 at 10:33

score 3 · Answer 6 · edited May 17 '17 at 06:14

3

You should define the below:

static class LOGOUT {
public:
    LOGOUT() {}
    std::ostream&  info() {
        std::cout << "[info      ] ";
        return std::cout;
    }

} logout;

using this:

logout.info() << "test: " << "log" << std::endl;

edited May 17 '17 at 06:14

Alex

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answered May 17 '17 at 01:56

허영주

31
1

How to send custom message in Google C++ Testing Framework?

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