cpp-mathmatic-vector/vector_test.cpp

//
//  vector_test.cpp
//  vector
//
//  Created by Sam Jaffe on 6/2/18.
//

#include <gmock/gmock.h>

#include "vector.hpp"

template <typename T, size_t N>
math::vector::vector<T, N> iota() {
  math::vector::vector<T, N> rval;
  for (size_t i = 0; i < N; ++i) rval[i] = static_cast<T>(i+1);
  return rval;
}

using vec2i = math::vector::vector<int, 2>;
using vec3  = math::vector::vector<double, 3>;
using vec3i = math::vector::vector<int, 3>;
using vec4i = math::vector::vector<int, 4>;

vec2i iota2i() { return iota<int, 2>(); }
vec3i iota3i() { return iota<int, 3>(); }

TEST(Vector, Equality) {
  EXPECT_THAT((iota3i()), (vec3i{{1, 2, 3}}));
  EXPECT_THAT((iota3i()), ::testing::Not(vec3i{{0, 2, 3}}));
}

TEST(Vector, DefaultConstructorIsAllZero) {
  EXPECT_THAT(vec3i(), (vec3i{{0,0,0}}));
}

TEST(Vector, ExtensionConstructorAppendsZeros) {
  EXPECT_THAT(vec4i(iota3i()), (vec4i{{1,2,3,0}}));
}

TEST(Vector, CanAccessVectorElements) {
  math::vector::vector<int, 3> viota = iota3i();
  EXPECT_THAT(viota[0], 1);
  EXPECT_THAT(viota[1], 2);
  EXPECT_THAT(viota[2], 3);
}

TEST(Vector, AccessingOutOfRangeThrows) {
  EXPECT_THROW(iota3i().at(3), std::out_of_range);
}

TEST(Vector, CrossProduct2DHasOnlyZElement) {
  EXPECT_THAT((vec2i{{1,1}}.cross(vec2i{{-1,1}})), (vec3i{{0,0,2}}));
}

TEST(Vector, CrossProduct3DHasAllElements) {
  EXPECT_THAT((vec3i{{1,1,2}}.cross(vec3i{{-1,1,1}})), (vec3i{{-1,-3,2}}));
}

TEST(Vector, AdditionIsPiecewise) {
  EXPECT_THAT((vec2i{{1,0}} + vec2i{{0,1}}), (vec2i{{1,1}}));
}

TEST(Vector, SubtractionIsPiecewise) {
  EXPECT_THAT((vec2i{{1,0}} - vec2i{{0,1}}), (vec2i{{1,-1}}));
}

TEST(Vector, MultiplicationIsPiecewise) {
  EXPECT_THAT((vec2i{{1,0}}*(vec2i{{2,1}})), (vec2i{{2,0}}));
}

TEST(Vector, DivisionIsPiecewise) {
  EXPECT_THAT((vec2i{{6,4}}/(vec2i{{2,1}})), (vec2i{{3,4}}));
}

TEST(Vector, DivisionByZeroThrowsException) {
  EXPECT_THROW(vec3{} / 0, std::domain_error);
  EXPECT_THROW((vec3{{1.0, 1.0, 1.0}}/(vec3{{1.0, 0.5, 0.0}})), std::domain_error);
}

//  TEST(Vector, AdditionWithValueType) {
//    EXPECT_THAT((vec2i{1,0} + 1), (vec2i{2,1}))
//    EXPECT_THAT(1+iota2i(), (vec2i{2,3}));
//  }
//
//  TEST(Vector, SubtractionWithValueType) {
//    EXPECT_THAT(4-iota2i(), (vec2i{3,2}));
//    EXPECT_THAT((vec2i{1,0} - 1), (vec2i{0,-1}))
//  }

TEST(Vector, MultiplicationWithValueType) {
  EXPECT_THAT((vec2i{{1,0}} * 3), (vec2i{{3,0}}));
  EXPECT_THAT(2*iota2i(), (vec2i{{2,4}}));
}

TEST(Vector, DivisionWithValueType) {
  EXPECT_THAT((vec2i{{6,4}} / 2), (vec2i{{3,2}}));
//  EXPECT_THAT(4/iota2i(), (vec2i{4,2}));
}

TEST(Vector, Length) {
  //    EXPECT_THAT(iota3i().lengthSquared(), 14);
  EXPECT_THAT(iota3i().magnitude(),
              ::testing::DoubleNear(std::sqrt(14), 0.00001));
}

TEST(Vector, Distance) {
  //    EXPECT_THAT((iota3i().distanceSquared(vec3i{3, 1, -1})), 21);
  EXPECT_THAT((iota3i() - vec3i{{3, 1, -1}}).magnitude(),
              ::testing::DoubleNear(std::sqrt(21), 0.00001));
}

TEST(Vector, Projection) {
  EXPECT_THAT((iota3i().projection(vec3i{{3, 1, -1}})).magnitude(),
              ::testing::DoubleNear(std::sqrt(4.0/11.0), 0.00001));
}

TEST(Vector, DotProductIsSumOfElementProducts) {
  EXPECT_THAT((iota3i().dot(vec3i{{3, 0, -1}})), 0);
}

TEST(Vector, UnitFunctionCreatesNewVectorOverMagnitude) {
  double sq = std::sqrt(14);
  auto unit = iota3i().unit();
  EXPECT_THAT(unit[0], ::testing::DoubleNear(1/sq, 0.00001));
  EXPECT_THAT(unit[1], ::testing::DoubleNear(2/sq, 0.00001));
  EXPECT_THAT(unit[2], ::testing::DoubleNear(3/sq, 0.00001));
}

TEST(Vector, CanCastEntireVectorThroughConstructor) {
  EXPECT_THAT((vec3i(vec3{{1.0, 2.3, 3.9}})), iota3i());
}

TEST(Vector, SwapExchangesAllValues) {
  using std::swap;
  vec2i a{{1, 2}}; const vec2i ac = a;
  vec2i b{{5, 7}}; const vec2i bc = b;
  swap(a, b);
  EXPECT_THAT(a, bc);
  EXPECT_THAT(b, ac);
}

TEST(Vector, UnaryNegateOperatorNegatesAllElements) {
  EXPECT_THAT(-iota3i(), (vec3i{{-1,-2,-3}}));
}

TEST(Vector, AbsoluteValueOfVectorAbsAllElements) {
  EXPECT_THAT(iota3i(), abs(-iota3i()));
}

TEST(Vector, MakeVectorAllowsConstuctionFromVariadicComponents) {
  EXPECT_TRUE((std::is_same<vec2i, decltype(make_vector(1, 2))>::value));
  EXPECT_THAT(iota2i(), make_vector(1, 2));
  EXPECT_FALSE((std::is_same<vec2i, decltype(make_vector(1, 2, 3))>::value));
  EXPECT_TRUE((std::is_same<vec3i, decltype(make_vector(1, 2, 3))>::value));
  EXPECT_THAT(iota3i(), make_vector(1, 2, 3));
}