Suppress output from google test assertions

Question

I have a couple of tests that test interpolations of continuous functions, and when my implementation fails for some reason I get lots of output like the following from my Google test suite:

/home/tlycken/exjobb/Code/alpha-orbit-follower/test/interpolation/interpolation-tests.cpp:71: Failure
The difference between this->test_function_y_deriv(x,y) and this->getInterpObjectPtr()->evaluateAt(x,y,0,1) is 1.5395837072062037, which exceeds tol, where
this->test_function_y_deriv(x,y) evaluates to -1.5395837072062037,
this->getInterpObjectPtr()->evaluateAt(x,y,0,1) evaluates to 0, and
tol evaluates to 0.01.

Since I basically loop over the interpolated interval and test with ASSERT_NEAR() in a lot of places, I'm not surprised, but it would be nice to suppress the details of each error message, and just see the pass/fail status of the test case in the report. If a test fails, and I don't understand why, I can reenable the output and look closer.

However, I can't find any information on how to suppress that kind of output. Perhaps my Google-fu is inadequate...

Is there a command line flag, or some other means, to suppress the output from individual ASSERT* calls, and just show the final test report?

Code sample:

As this seems to be difficult to reproduce, this is the code I'm running. In my test fixture, I have the following method:

void on_interpolated_grid(std::function<void(double)> f) {
    double dxp = dx / 10;
    double xmax = xmin + (N - 1) * dx;

    for (double xp = xmin + 2 * dx; xp < xmax - 2 * dx; xp += dxp) {
        f(xp);
    }
}

and the test is defined like this:

TYPED_TEST(Interp1D_F, SecondOrderDerivative) {
    Interp1D itp(this->N, this->x, this->f);

    this->on_interpolated_grid([itp](double x) -> void {
        ASSERT_NEAR(-sin(x), itp.evaluateAt(x, 2), 1e-3);
    });
}

The members N , x and f on the test fixture are just parameters for initialization of the interpolation object.

I also tried to wrap the call to on_interpolated_grid in ASSERT_NO_FATAL_FAILURES , but it didn't help.

Answer 1

As far as I can see, the problem results from the fact that ASSERT_NEAR behaves more like EXPECT_NEAR in this case.

The reason for this behavior is that Google Test uses return but no exceptions in ASSERT_* . See their FAQ for why they do this (in short: it allows to run tests even with exceptions disabled but has other advantages in some cases like ASSERT in try -blocks.

The downside of this approach is exactly what you have here: ASSERT_ does not propagate fatal failures if used in subfunctions (or a lambda as in your case). The GTest Advanced topics page has a section regarding this problem . With HasFatalFailure() your situation can be solved with a modified lambda method:

#include "gtest/gtest.h"
#include "gtest/gtest-typed-test.h"
#include <functional>

void on_interpolated_grid(std::function<void(double)> f) {
    ///ADDED a few values here
    double dxp = 1.0 / 10.0;
    double xmin = 0.1;
    double dx = 0.1;
    int N = 100;
    double xmax = xmin + (N - 1) * dx;

    for (double xp = xmin + 2 * dx; xp < xmax - 2 * dx; xp += dxp) {
        f(xp);
    }
}



TEST(Interp1D_F, SecondOrderDerivative) {
    ///REMOVED. Not required for sample
    //Interp1D itp(this->N, this->x, this->f);

    on_interpolated_grid([](double x) -> void {
        ///ADDED:
        //Only check for further failures if no previous fatal failure ocurred
        if (!this->HasFatalFailure())
            ASSERT_NEAR(-sin(x),0 , 1e-3);

    });
}

To see the full test output (if desired), you just remove the added line.

Answer 2

Recently I asked similar question ( Reducing output of gtest, to look similar to output of cxxtest ).

If you want to fully suppress the output, you can use ::testing::EmptyTestEventListener . For anything fancy, you have to implement custom listener (see for example here ).

You can even add an option in main() to change the listener depending on program parameters.

You said that you want colorful output. googletest's maintainers added functions to print text in color. I know you shouldn't, but if you declare those functions, you will get access to them.

Answer 3

It seems google test AssertionResult are printed to standard output by design. No built-in command line option to disable specific parts of the that output either.

If tweaking google test itself is an option, then the easiest would probably be to add a condition around the PrintTestPartResult call in PrettyUnitTestResultPrinter::OnTestPartResult , and similarly with calls to PrintFullTestCommentIfPresent in OnTestEnd / PrintFailedTests . In that case, your own option to control verbosity could be included in ParseGoogleTestFlagsOnlyImpl and kColorEncodedHelpMessage .

Otherwise (ie if recompiling google test is not an option), it is possible to write a TestEventListener replacement to the default PrettyUnitResultPrinter (possibly inspired from PrettyUnitResultPrinter itself), as documented in google test samples .