How to check if the test failed in Google Test TearDown()?

At the end of every "file based integration" test, I want to clear a temp folder of associated files.

If the test fails, I want to leave the files there, so I can review the unexpected output.

Is there a way in the Google Test TearDown to check if the test has failed?

Is there a way in the Google Test TearDown to check if the test has failed?

Yes, you can do that be querying ::testing::Test::HasFailure() in the test cases of your fixture and using the result to tally failures in a counter member of the fixture that can be queried in its TearDown(). An elementary example:

#include <gtest/gtest.h>
#include <iostream>

struct Fixture : public ::testing::Test {
    virtual void SetUp() {
        fails = 0;
    }

    virtual void TearDown() {
        if (fails > 0) {
            std::cerr << "Fixture::TearDown sees failures" << std::endl;
        }
    }

    unsigned fails;
};

TEST_F(Fixture, foo) {
    EXPECT_EQ(1,0);
    fails += ::testing::Test::HasFailure();
}
TEST_F(Fixture, bar) {
    EXPECT_EQ(1,1);
    fails += ::testing::Test::HasFailure();
}

int main(int argc, char **argv) {
  testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

And output:

[==========] Running 2 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 2 tests from Fixture
[ RUN      ] Fixture.foo
/home/imk/dev/so/gtest/main.cpp:19: Failure
      Expected: 1
To be equal to: 0
Fixture::TearDown sees failures
[  FAILED  ] Fixture.foo (0 sec)
[ RUN      ] Fixture.bar
[       OK ] Fixture.bar (0 sec)
[----------] 2 tests from Fixture (0.001 sec total)

[----------] Global test environment tear-down
[==========] 2 tests from 1 test case ran. (1 ms total)
[  PASSED  ] 1 test.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] Fixture.foo

 1 FAILED TEST