cpp-json/test/json_binder_polymorphic_test.cxx

//
//  json_binder_polymorphic.t.h
//  json
//
//  Created by Sam Jaffe on 11/14/18.
//  Copyright © 2018 Sam Jaffe. All rights reserved.
//

#include <gmock/gmock.h>
#include "json/json_binder.hpp"

struct Base {
  virtual ~Base() = default;
  virtual void run() const = 0;
};

struct Left : public Base {
  int a;
  void run() const override {}
};

struct Right : public Base {
  std::string a;
  void run() const override {}
};

bool operator==(Left const & lhs, Left const & rhs) {
  return lhs.a == rhs.a;
}

bool operator==(Right const & lhs, Right const & rhs) {
  return lhs.a == rhs.a;
}

using namespace json::binder;
using namespace json::parser;

class JsonBinderPolymorphicTest : public ::testing::Test {
protected:
  using pBase = std::unique_ptr<Base>;

  polymorphic_binder<pBase> & GetBinder() {
    static polymorphic_binder<pBase> val = polymorphic_binder<pBase>()
    ("Left", object_binder<Left>()("a", &Left::a))
    ("Right", object_binder<Right>()("a", &Right::a));
    return val;
  }
};

template <typename T>
bool instanceof(Base * ptr) {
  return dynamic_cast<T*>(ptr) != nullptr;
}

using namespace ::testing;

TEST_F(JsonBinderPolymorphicTest, CanHitLeftPolymorph) {
  char data[] = "{\"@id\":\"Left\", \"@value\":{\"a\":1}}";
  pBase out;
  Left expected; expected.a = 1;
  EXPECT_NO_THROW(parse(json::binder::bind(out, GetBinder()), data));
  EXPECT_THAT(out, Not(IsNull()));
  EXPECT_PRED1(instanceof<Left>, out.get());
  EXPECT_THAT(dynamic_cast<Left&>(*out), expected);
}

TEST_F(JsonBinderPolymorphicTest, CanHitRightPolymorph) {
  char data[] = "{\"@id\":\"Right\", \"@value\":{\"a\":\"hello\"}}";
  pBase out;
  Right expected; expected.a = "hello";
  EXPECT_NO_THROW(parse(json::binder::bind(out, GetBinder()), data));
  EXPECT_THAT(out, Not(IsNull()));
  EXPECT_PRED1(instanceof<Right>, out.get());
  EXPECT_THAT(dynamic_cast<Right&>(*out), expected);
}