cpp-reflection/test/object_test.cxx

//
//  object_test.cxx
//  reflection-test
//
//  Created by Sam Jaffe on 7/4/22.
//  Copyright © 2022 Sam Jaffe. All rights reserved.
//

#include "reflection/object.h"

#include "xcode_gtest_helper.h"

using reflection::Object;
using reflection::Reflection;

using testing::Eq;
using testing::NotNull;

namespace {
struct Example {
  int a;

  int get_c() const { return a + 4; }
  void set_c(int c) { a = c - 4; }
};

struct Compound {
  Example ex;
};
}

namespace reflection {
INSTANTIATE_REFLECTION(Example);
INSTANTIATE_REFLECTION(Compound);
}

REFLECTION(Example)
    .bind("a", &Example::a)
    .bind("c", &Example::get_c, &Example::set_c);

REFLECTION(Compound).bind("ex", &Compound::ex);

TEST(ObjectTest, CanFetchData) {
  Example ex{.a = 1};

  Object a = Object(ex).get("a");

  EXPECT_NO_THROW((void)int(a)) << a.type().name();
  EXPECT_THAT(int(a), 1);
}

TEST(ObjectTest, CanSetDataOnNonConst) {
  Example ex{.a = 1};

  {
    Object a = Object(ex).get("a");
    EXPECT_NO_THROW((void)static_cast<int &>(a)) << a.type().name();
    static_cast<int &>(a) = 2;
  }
  EXPECT_THAT(ex.a, 2);
}

TEST(ObjectTest, ThrowsWhenTryingToEditConst) {
  Example const ex{.a = 1};

  Object a = Object(ex).get("a");
  EXPECT_THROW((void)static_cast<int &>(a), std::bad_cast);
}

TEST(ObjectTest, ThrowsWhenTryingToEditMoved) {
  Object a = Object(Example{.a = 1}).get("a");
  EXPECT_THROW((void)static_cast<int &>(a), std::bad_cast);
}

TEST(ObjectTest, ThrowsWhenPerformingTypeCoersion) {
  Example const ex{.a = 1};

  Object a = Object(ex).get("a");
  EXPECT_THROW((void)double(a), std::bad_cast);
}

TEST(ObjectTest, CanFetchWithGetter) {
  Example ex{.a = 1};

  Object c = Object(ex).get("c");
  EXPECT_NO_THROW((void)int(c)) << c.type().name();
  EXPECT_THAT(int(c), Eq(5));
  static_cast<int &>(c) = 4;
}

TEST(ObjectTest, CanModifyWithSetter) {
  Example ex{.a = 1};

  {
    Object c = Object(ex).get("c");
    EXPECT_NO_THROW((void)static_cast<int &>(c)) << c.type().name();
    static_cast<int &>(c) = 4;
    // Notice that the setter is scoped on the Object expiring
    EXPECT_THAT(ex.a, Eq(1));
  }

  EXPECT_THAT(ex.a, Eq(0));
}

TEST(ObjectTest, ThrowsWhenUsingSetterOnConst) {
  Example const ex{.a = 1};

  Object c = Object(ex).get("c");
  EXPECT_THROW((void)static_cast<int &>(c), std::bad_cast);
}

TEST(ObjectTest, CanDive) {
  Compound cm{.ex = {.a = 2}};

  Object a = Object(cm).get(std::vector{"ex", "a"});
  EXPECT_NO_THROW((void)int(a));
  EXPECT_THAT(int(a), Eq(2));
}

TEST(ObjectTest, AttachesNameInfo) {
  Compound cm{.ex = {.a = 2}};

  Object a = Object(cm).get(std::vector{"ex", "a"});
  EXPECT_THAT(a.path(), Eq("this.ex.a"));
  EXPECT_THAT(a.name(), Eq("a"));
}

TEST(ObjectTest, CanReflectVariableName) {
  Compound cm{.ex = {.a = 2}};

  Object a = reflect(cm).get(std::vector{"ex", "a"});
  EXPECT_THAT(a.path(), Eq("cm.ex.a"));
  EXPECT_THAT(a.name(), Eq("a"));
}