sqlgen/tests/postgres/test_left_join.cpp

#ifndef SQLGEN_BUILD_DRY_TESTS_ONLY

#include <gtest/gtest.h>

#include <optional>
#include <rfl.hpp>
#include <rfl/json.hpp>
#include <sqlgen.hpp>
#include <sqlgen/postgres.hpp>
#include <vector>

namespace test_left_join {

TEST(postgres, test_left_join) {
  struct Person {
    sqlgen::PrimaryKey<uint32_t> id;
    std::string first_name;
    std::string last_name;
  };

  struct Pet {
    sqlgen::PrimaryKey<uint32_t> id;
    std::string name;
    uint32_t owner_id;
  };

  const auto people = std::vector<Person>({
      Person{.id = 1, .first_name = "Homer", .last_name = "Simpson"},
      Person{.id = 2, .first_name = "Marge", .last_name = "Simpson"},
      Person{.id = 3, .first_name = "Bart", .last_name = "Simpson"},
      Person{.id = 4, .first_name = "Lisa", .last_name = "Simpson"},
  });

  const auto pets = std::vector<Pet>({
      Pet{.id = 1, .name = "Santa's Little Helper", .owner_id = 1},
      Pet{.id = 2, .name = "Snowball", .owner_id = 4},
      Pet{.id = 3, .name = "Mr. Teeny", .owner_id = 99},
  });

  const auto credentials = sqlgen::postgres::Credentials{.user = "postgres",
                                                         .password = "password",
                                                         .host = "localhost",
                                                         .dbname = "postgres"};

  using namespace sqlgen;
  using namespace sqlgen::literals;

  struct PersonWithPet {
    std::string first_name;
    std::string last_name;
    std::optional<std::string> pet_name;
  };

  const auto get_people_with_pets =
      select_from<Person, "t1">("first_name"_t1 | as<"first_name">,
                                "last_name"_t1 | as<"last_name">,
                                "name"_t2 | as<"pet_name">) |
      left_join<Pet, "t2">("id"_t1 == "owner_id"_t2) | order_by("id"_t1) |
      to<std::vector<PersonWithPet>>;

  const auto result = postgres::connect(credentials)
                          .and_then(drop<Person> | if_exists)
                          .and_then(drop<Pet> | if_exists)
                          .and_then(write(std::ref(people)))
                          .and_then(write(std::ref(pets)))
                          .and_then(get_people_with_pets)
                          .value();

  const std::string expected_query =
      R"(SELECT t1."first_name" AS "first_name", t1."last_name" AS "last_name", t2."name" AS "pet_name" FROM "Person" t1 LEFT JOIN "Pet" t2 ON t1."id" = t2."owner_id" ORDER BY t1."id")";
  const std::string expected_json =
      R"([{"first_name":"Homer","last_name":"Simpson","pet_name":"Santa's Little Helper"},{"first_name":"Marge","last_name":"Simpson"},{"first_name":"Bart","last_name":"Simpson"},{"first_name":"Lisa","last_name":"Simpson","pet_name":"Snowball"}])";

  EXPECT_EQ(postgres::to_sql(get_people_with_pets), expected_query);
  EXPECT_EQ(rfl::json::write(result), expected_json);
}

}  // namespace test_left_join

#endif