Method MatchAndExplain

cpp/src/arrow/testing/matchers.h:295–302

      void DescribeNegationTo(::std::ostream* os) const override { *os << "is not ok"; }

      bool MatchAndExplain(const Res& maybe_value,
                           testing::MatchResultListener* listener) const override {
        const Status& status = ToStatus(maybe_value);

        const bool match = status.ok();
        *listener << "whose " << (match ? "non-error matches" : "error doesn't match");
        return match;
      }
    };

    return testing::Matcher<Res>(new Impl());