Function TEST

cpp/src/arrow/compute/expression_test.cc:95–127

const auto no_change = std::nullopt;

TEST(ExpressionUtils, Comparison) {
  auto cmp_name = [](Datum l, Datum r) {
    return Comparison::Execute(l, r).Map(Comparison::GetName);
  };

  Datum zero(0), one(1), two(2), null(std::make_shared<Int32Scalar>());
  Datum str("hello"), bin(std::make_shared<BinaryScalar>(Buffer::FromString("hello")));
  Datum dict_str(DictionaryScalar::Make(std::make_shared<Int32Scalar>(0),
                                        ArrayFromJSON(utf8(), R"(["a", "b", "c"])")));

  auto RaisesNotImpl =
      Raises(StatusCode::NotImplemented, HasSubstr("no kernel matching input types"));

  EXPECT_THAT(cmp_name(one, one), ResultWith(Eq("equal")));
  EXPECT_THAT(cmp_name(one, two), ResultWith(Eq("less")));
  EXPECT_THAT(cmp_name(one, zero), ResultWith(Eq("greater")));

  EXPECT_THAT(cmp_name(one, null), ResultWith(Eq("na")));
  EXPECT_THAT(cmp_name(null, one), ResultWith(Eq("na")));

  // strings and ints are not comparable without explicit casts
  EXPECT_THAT(cmp_name(str, one), RaisesNotImpl);
  EXPECT_THAT(cmp_name(one, str), RaisesNotImpl);
  EXPECT_THAT(cmp_name(str, null), RaisesNotImpl);  // not even null ints

  // string -> binary implicit cast allowed
  EXPECT_THAT(cmp_name(str, bin), ResultWith(Eq("equal")));
  EXPECT_THAT(cmp_name(bin, str), ResultWith(Eq("equal")));

  // dict_str -> string, implicit casts allowed
  EXPECT_THAT(cmp_name(dict_str, str), ResultWith(Eq("less")));
  EXPECT_THAT(cmp_name(dict_str, bin), ResultWith(Eq("less")));
}

TEST(ExpressionUtils, StripOrderPreservingCasts) {
  auto Expect = [](Expression expr, std::optional<Expression> expected_stripped) {