New Test Fixture for each iteration over enum members - googletest

Question

My tests are contained within functions declared with TEST_F so that I can use a new test fixture object between tests. For each TEST_F, a new instance of the test fixture is created. But what if I wish to loop over an enum in my test and have a new instance of the test fixture for each iteration? What should I do in this case?

Answer 1

It sounds like you want to use value-parameterized tests.
You could iterate through the values of an enum like this:
#include <iostream>
#include "gtest/gtest.h"
enum Malt { bowmore = 10, talisker, scapa };
class Whisky {
public:
explicit Whisky(const Malt& malt) : malt_(malt) {}
bool IsIslay() const { return malt_ == bowmore; }
private:
Malt malt_;
};
class DramTest : public testing::TestWithParam<Malt> {
protected:
DramTest() : whisky_(GetParam()) {}
Whisky whisky_;
};
TEST_P(DramTest, IsIslay) {
if (GetParam() == bowmore)
EXPECT_TRUE(whisky_.IsIslay());
else
EXPECT_FALSE(whisky_.IsIslay());
}
INSTANTIATE_TEST_CASE_P(AllMalts, DramTest,
testing::Values(bowmore, talisker, scapa));
int main(int argc, char **argv) {
testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
If you have a large number of enum values, you could use the Range generator instead of the Value one:
testing::Range<int>(bowmore, scapa + 1)
but this needs some casting in the fixture between ints and the enum type.
Both options suffer from maintenance problems; if you add a new enum value, you need to remember to change the test.