westonpace commented on a change in pull request #9643: URL: https://github.com/apache/arrow/pull/9643#discussion_r598939293
########## File path: cpp/src/arrow/util/stl_util_test.cc ########## @@ -92,5 +93,66 @@ TEST(StlUtilTest, ArgSortPermute) { ExpectSortPermutation({b, c, d, e, a, f}, {4, 0, 1, 2, 3, 5}, 2); } +TEST(StlUtilTest, VectorFlatten) { + std::vector<int> a{1, 2, 3}; + std::vector<int> b{4, 5, 6}; + std::vector<int> c{7, 8, 9}; + std::vector<std::vector<int>> vecs{a, b, c}; + auto actual = FlattenVectors(vecs); + std::vector<int> expected{1, 2, 3, 4, 5, 6, 7, 8, 9}; + ASSERT_EQ(expected, actual); +} + +TEST(StlUtilTest, VectorMap) { + std::vector<int> input{1, 2, 3}; + std::vector<std::string> expected{"1", "2", "3"}; + auto actual = MapVector([](int item) { return std::to_string(item); }, input); Review comment: No. There is a comment in `call_traits`(which I use to determine the return type): `/// TODO(bkietz) support function pointers` I tried a few `decltype` alternatives just now and couldn't make any headway. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org