cpp-mathmatic-matrix/matrix_test.cpp

//
//  matrix_test.cpp
//  matrix
//
//  Created by Sam Jaffe on 6/3/18.
//

#include <gmock/gmock.h>

#include "matrix.hpp"
#include "matrix_helpers.hpp"

using matr2i = math::matrix::matrix<int, 2, 2>;
using matr2 = math::matrix::matrix<double, 2, 2>;

TEST(Matrix, Equality) {
  using math::matrix::identity;
  EXPECT_THAT((identity<int, 2>()), matr2i({{{1,0},{0,1}}}));
}

TEST(Matrix, AdditionSumsAllElements) {
  auto iden = math::matrix::identity<int, 2>();
  auto result = matr2i({{{2,0},{0,2}}});
  EXPECT_THAT(iden + iden, result);
}

TEST(Matrix, DefaultConstructorIsZeros) {
  auto zero = matr2i({{{0,0},{0,0}}});
  EXPECT_THAT(matr2i{}, zero);
}

TEST(Matrix, SubtractionDiffsAllElements) {
  auto zero = matr2i({{{0,0},{0,0}}});
  auto iden = math::matrix::identity<int, 2>();
  EXPECT_THAT(iden-iden, zero);
}

TEST(Matrix, NegationAltersAllElements) {
  auto iden = math::matrix::identity<int, 2>();
  EXPECT_THAT(-iden, matr2i({{{-1,0},{0,-1}}}));
}

TEST(Matrix, _matrix_scaling) {
  auto iden = math::matrix::identity<double, 2>();
  EXPECT_THAT(2*iden, matr2({{{2.0,0.0},{0.0,2.0}}}));
  EXPECT_THAT(iden*2, matr2({{{2.0,0.0},{0.0,2.0}}}));
  EXPECT_THAT(iden/2.0, matr2({{{0.5,0.0},{0.0,0.5}}}));
}

TEST(Matrix, MultiplyingSameSizeMatricesProducesSameSize) {
  auto A = matr2i({{{1,2},{2,3}}});
  auto B = matr2i({{{1,0},{1,1}}});
  EXPECT_THAT(A*B, matr2i({{{3,2},{5,3}}}));
  EXPECT_THAT(B*A, matr2i({{{1,2},{3,5}}}));
}

TEST(Matrix, MultiplyingDifferentSizeMatricesChangesSize) {
  using matr2x2i = math::matrix::matrix<int, 2, 2>;
  using matr2x3i = math::matrix::matrix<int, 2, 3>;
  using matr3x2i = math::matrix::matrix<int, 3, 2>;
  using matr3x3i = math::matrix::matrix<int, 3, 3>;
  auto A = matr3x2i({{{1,0},{0,1},{1,1}}});
  auto B = matr2x3i({{{0,1,0},{1,0,1}}});
  EXPECT_THAT(A*B, matr3x3i({{{0,1,0},{1,0,1},{1,1,1}}}));
  EXPECT_THAT(B*A, matr2x2i({{{0,1},{2,1}}}));
}

TEST(Matrix, VectorMultiplicationProducesVector) {
  using vec2i = math::vector::vector<int, 2>;
  auto A = matr2i({{{1,0},{1,2}}});
  auto x = vec2i({1,2});
  EXPECT_THAT(A*x, vec2i({1,5}));
}

//TEST(Matrix, Composition) {
//  using namespace math::matrix;
//  using vec4 = math::vector::vector<double, 4>;
//  using vec3 = math::vector::vector<double, 3>;
//  auto rot = rotation<4>(math::degree{90}, rotate::X_AXIS);
//  auto mov = translation(vec3({2.0, 2.5, 1.5}));
//  auto scl = scalar(vec3(2.0, math::vector::fill));
//  vec4 epsilon{0.00001, math::vector::fill};
//  TS_ASSERT_DELTA((mov * scl * rot * vec4({1,2,3,1})),
//                  (vec4({4.0,-1.5,-4.5,1.0})),
//                  epsilon);
//}

TEST(Matrix, MatrixConstructableFromVector) {
  using vec3 = math::vector::vector<double, 3>;
  vec3 v = vec3({1,2,3});
  math::matrix::matrix<double, 3, 1> m{v};
  EXPECT_THAT(m(0,0), v[0]);
  EXPECT_THAT(m(1,0), v[1]);
  EXPECT_THAT(m(2,0), v[2]);
}

TEST(Matrix, CanAlterEntireRowInOneExpression) {
  matr2i A = math::matrix::identity<int, 2>();
  matr2i const B = 2 * A;
  A[0] = B[0];
  EXPECT_THAT(A, matr2i({{{2,0},{0,1}}}));
}