cpp-opaque-typedef/opaque_typedef_test.cpp

//
//  opaque_typedef_test.cpp
//  opaque_typedef
//
//  Created by Sam Jaffe on 6/3/18.
//

#include <gmock/gmock.h>
#include <cmath>

#include "opaque_typedef.hpp"

struct degree;
struct radian;

CREATE_CONVERTABLE_OPAQUE_TYPEDEF(degree, double, orderable)(radian);
CREATE_CONVERTABLE_OPAQUE_TYPEDEF(radian, double, orderable)(degree);

radian::operator degree() const {
  return degree{ self() * 90.0 / M_PI_2 };
}

degree::operator radian() const {
  return radian{ self() * M_PI_2 / 90.0 };
}

void PrintTo(radian const & ot, std::ostream * os) {
  (*os) << double(ot)/M_PI << "π";
}

void PrintTo(degree const & ot, std::ostream * os) {
  (*os) << double(ot) << "°";
}

TEST(OpaqueTypedefTest, Conversion) {
  degree deg{90.0};
  radian rad{M_PI_2};
  
  EXPECT_THAT(radian(deg), rad);
  EXPECT_THAT(degree(rad), deg);
  EXPECT_THAT(radian(double(deg)), ::testing::Not(rad));
  EXPECT_THAT(degree(double(rad)), ::testing::Not(deg));
}

struct meters;
struct seconds;
struct meter_per_second;
CREATE_OPAQUE_TYPEDEF(seconds, double, orderable);
CREATE_OPAQUE_TYPEDEF(meter_per_second, double, orderable);
template <typename T> using mix_multiplication = mixed_multiplication<meters, seconds, meter_per_second>;
CREATE_OPAQUE_TYPEDEF(meters, double, orderable, mix_multiplication);

TEST(OpaqueTypedefTest, MixedFunctions) {
  meters m{10.0};
  seconds s{0.5};
  
  EXPECT_THAT(m*s, meter_per_second{5.0});
}