Exposition of the problem:
> cat main.cpp
TEST(errnoTest, errnoTest)
{
ASSERT_EQ(errno, 0);
}
int main(int argc, char** argv)
{
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Compiled with gcc 10 like this:
> g++ -pthread -o runtest main.cpp -Wl,-Bstatic -lgtest -Wl,-Bdynamic
Before patch:
> ./runtest
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from errnoTest
[ RUN ] errnoTest.errnoTest
[ OK ] errnoTest.errnoTest (0 ms)
[----------] 1 test from errnoTest (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[ PASSED ] 1 test.
(output is colored, I run this inside an interactive terminal).
> ./runtest | cat
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from errnoTest
[ RUN ] errnoTest.errnoTest
main.cpp:5: Failure
Expected equality of these values:
(*__errno_location ())
Which is: 25
0
[ FAILED ] errnoTest.errnoTest (0 ms)
[----------] 1 test from errnoTest (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[ PASSED ] 0 tests.
[ FAILED ] 1 test, listed below:
[ FAILED ] errnoTest.errnoTest
1 FAILED TEST
(output is not colored, since IsTTY return false, because of the pipe,
however it also clobbered errno for the tests).
After the patch, both cases are working fine:
> ./runtest
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from errnoTest
[ RUN ] errnoTest.errnoTest
[ OK ] errnoTest.errnoTest (0 ms)
[----------] 1 test from errnoTest (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[ PASSED ] 1 test.
> ./runtest | cat
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from errnoTest
[ RUN ] errnoTest.errnoTest
[ OK ] errnoTest.errnoTest (0 ms)
[----------] 1 test from errnoTest (0 ms total)
[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[ PASSED ] 1 test.
