cpp-descriptive-pointers/test/value_ptr_test.cxx

//
//  copy_ptr.t.h
//  pointers
//
//  Created by Sam Jaffe on 1/5/17.
//

#include "pointers/value_ptr.hpp"

#include <stdexcept>

#include <gmock/gmock.h>

#include "test_stubs.h"

struct copy_me {};
struct copy_me_throw {};

namespace pointers { namespace detail {
  template <> class value_ptr_copy<copy_me_throw> {
  protected:
    copy_me_throw * Copy(copy_me_throw const * p) const {
      if (p == nullptr) { throw std::runtime_error{"NULL"}; }
      return new copy_me_throw{*p};
    }
  };
}}

class base {
public:
  virtual ~base() {}
  virtual base * clone() const = 0;
  virtual int id() const = 0;
};

class derived_0 : public base {
public:
  static const constexpr int ID = 0;
  virtual base * clone() const override { return new derived_0; }
  virtual int id() const override { return ID; }
};

class derived_1 : public base {
public:
  static const constexpr int ID = 1;
  virtual base * clone() const override { return new derived_1; }
  virtual int id() const override { return ID; }
};

using namespace pointers;

TEST(ValuePtrTest, CanCopySimpleObject) {
  value_ptr<copy_me> c1{new copy_me};
  value_ptr<copy_me> c2{c1};
  EXPECT_THAT(c1.get(), testing::Not(c2.get()));
}

TEST(ValuePtrTest, CopyCtorIsNullSafe) {
  value_ptr<copy_me> c1{nullptr};
  value_ptr<copy_me> c2{c1};
  EXPECT_THAT(c1.get(), testing::IsNull());
  EXPECT_THAT(c1.get(), c2.get());
}

TEST(ValuePtrCustomTest, CanCopyWithCustomFunction) {
  using ptr_t = value_ptr<copy_me_throw>;
  value_ptr<copy_me_throw> c1{new copy_me_throw};
  value_ptr<copy_me_throw> c2{c1};
  EXPECT_THAT(c1.get(), testing::Not(c2.get()));
}

TEST(ValuePtrCustomTest, CustomCopyFunctionCanThrow) {
  value_ptr<copy_me_throw> c1{nullptr};
  EXPECT_THROW(value_ptr<copy_me_throw>{c1}, std::runtime_error);
}

TEST(ValuePtrTest, CopiedValueDeeplyEqualButNotSameAddress) {
  std::vector<int> my_vec = {1, 3, 5, 3, 6, 1, 2, -1, 0};
  value_ptr<std::vector<int>> c1{new std::vector<int>{my_vec}};
  EXPECT_THAT(*c1, my_vec);
  value_ptr<std::vector<int>> c2{c1};
  EXPECT_THAT(*c2, *c1);
  EXPECT_THAT(c2.get(), testing::Not(c1.get()));
}

TEST(ValuePtrPolymorphicTest, CanConstructPtrToBaseFromDerivedClasses) {
  value_ptr<base> c0{new derived_0};
  EXPECT_THAT(c0->id(), derived_0::ID);
  value_ptr<base> c1{new derived_1};
  EXPECT_THAT(c1->id(), derived_1::ID);
}

TEST(ValuePtrPolymorphicTest, CanConstructFromNullptr) {
  value_ptr<base> c1{nullptr};
  value_ptr<base> c2{c1};
  EXPECT_THAT(c1.get(), testing::IsNull());
  EXPECT_THAT(c1.get(), c2.get());
}

TEST(ValuePtrTest, OwnsGivenObject) {
  bool has_delete{false};
  destructor_sentinal * test_struct = new destructor_sentinal{has_delete};
  // I cannot actually copy-construct from a pointer for safety
  EXPECT_NO_THROW(value_ptr<destructor_sentinal>{std::move(test_struct)});
  EXPECT_TRUE(has_delete);
}

TEST(ValuePtrTest, OwnsTemporaryObject) {
  bool has_delete{false};
  EXPECT_NO_THROW(
      value_ptr<destructor_sentinal>{new destructor_sentinal{has_delete}});
  EXPECT_TRUE(has_delete);
}

TEST(ValuePtrTest, FactoryMethodProducesCopy) {
  int deleted{0};
  {
    std::unique_ptr<destructor_ctr> test_struct{new destructor_ctr{deleted}};
    EXPECT_NO_THROW(value_ptr<destructor_ctr>::copy_of(test_struct.get()));
    EXPECT_THAT(deleted, 1);
  }
  EXPECT_THAT(deleted, 2);
}