Vec3/tests/unit_tests/vec_test.cpp

#include "vec3.h"
#include <cmath>
#include <gtest/gtest.h>
#include <limits>

// Test fixture for Vec3 tests
class Vec3Test : public ::testing::Test {
protected:
  // Test vectors that will be used across multiple tests
  Vec3<int> int_vec1, int_vec2;
  Vec3<float> float_vec1, float_vec2;
  Vec3<double> double_vec1, double_vec2;

  void SetUp() override {
    // Initialize test vectors
    int_vec1 = {1, 2, 3};
    int_vec2 = {4, 5, 6};

    float_vec1 = {1.5f, 2.5f, 3.5f};
    float_vec2 = {4.5f, 5.5f, 6.5f};

    double_vec1 = {1.5, 2.5, 3.5};
    double_vec2 = {4.5, 5.5, 6.5};
  }
};

// Test vector addition
TEST_F(Vec3Test, Addition) {
  // Test integer vectors
  auto int_result = int_vec1 + int_vec2;
  EXPECT_EQ(int_result.x, 5);
  EXPECT_EQ(int_result.y, 7);
  EXPECT_EQ(int_result.z, 9);

  // Test float vectors
  auto float_result = float_vec1 + float_vec2;
  EXPECT_FLOAT_EQ(float_result.x, 6.0f);
  EXPECT_FLOAT_EQ(float_result.y, 8.0f);
  EXPECT_FLOAT_EQ(float_result.z, 10.0f);

  // Test double vectors
  auto double_result = double_vec1 + double_vec2;
  EXPECT_DOUBLE_EQ(double_result.x, 6.0);
  EXPECT_DOUBLE_EQ(double_result.y, 8.0);
  EXPECT_DOUBLE_EQ(double_result.z, 10.0);
}

// Test vector subtraction
TEST_F(Vec3Test, Subtraction) {
  // Test integer vectors
  auto int_result = int_vec2 - int_vec1;
  EXPECT_EQ(int_result.x, 3);
  EXPECT_EQ(int_result.y, 3);
  EXPECT_EQ(int_result.z, 3);

  // Test float vectors
  auto float_result = float_vec2 - float_vec1;
  EXPECT_FLOAT_EQ(float_result.x, 3.0f);
  EXPECT_FLOAT_EQ(float_result.y, 3.0f);
  EXPECT_FLOAT_EQ(float_result.z, 3.0f);

  // Test double vectors
  auto double_result = double_vec2 - double_vec1;
  EXPECT_DOUBLE_EQ(double_result.x, 3.0);
  EXPECT_DOUBLE_EQ(double_result.y, 3.0);
  EXPECT_DOUBLE_EQ(double_result.z, 3.0);
}

// Test vector scaling
TEST_F(Vec3Test, Scale) {
  // Test integer scaling
  Vec3<int> int_vec_scaled = int_vec1;
  int_vec_scaled.scale(2);
  EXPECT_EQ(int_vec_scaled.x, 2);
  EXPECT_EQ(int_vec_scaled.y, 4);
  EXPECT_EQ(int_vec_scaled.z, 6);

  // Test float scaling
  Vec3<float> float_vec_scaled = float_vec1;
  float_vec_scaled.scale(2.0f);
  EXPECT_FLOAT_EQ(float_vec_scaled.x, 3.0f);
  EXPECT_FLOAT_EQ(float_vec_scaled.y, 5.0f);
  EXPECT_FLOAT_EQ(float_vec_scaled.z, 7.0f);

  // Test double scaling
  Vec3<double> double_vec_scaled = double_vec1;
  double_vec_scaled.scale(2.0);
  EXPECT_DOUBLE_EQ(double_vec_scaled.x, 3.0);
  EXPECT_DOUBLE_EQ(double_vec_scaled.y, 5.0);
  EXPECT_DOUBLE_EQ(double_vec_scaled.z, 7.0);

  // Test scaling by zero
  Vec3<float> zero_scaled = float_vec1;
  zero_scaled.scale(0.0f);
  EXPECT_FLOAT_EQ(zero_scaled.x, 0.0f);
  EXPECT_FLOAT_EQ(zero_scaled.y, 0.0f);
  EXPECT_FLOAT_EQ(zero_scaled.z, 0.0f);

  // Test scaling by negative number
  Vec3<int> neg_scaled = int_vec1;
  neg_scaled.scale(-1);
  EXPECT_EQ(neg_scaled.x, -1);
  EXPECT_EQ(neg_scaled.y, -2);
  EXPECT_EQ(neg_scaled.z, -3);
}

// Test dot product
TEST_F(Vec3Test, DotProduct) {
  // Test integer dot product
  int int_dot = int_vec1.dot(int_vec2);
  EXPECT_EQ(int_dot, 32); // 1*4 + 2*5 + 3*6 = 4 + 10 + 18 = 32

  // Test float dot product
  float float_dot = float_vec1.dot(float_vec2);
  EXPECT_FLOAT_EQ(
      float_dot,
      43.25f); // 1.5*4.5 + 2.5*5.5 + 3.5*6.5 = 6.75 + 13.75 + 22.75 = 43.25

  // Test double dot product
  double double_dot = double_vec1.dot(double_vec2);
  EXPECT_DOUBLE_EQ(double_dot, 43.25); // Same calculation as float

  // Test dot product with self (should equal squared length)
  int self_dot = int_vec1.dot(int_vec1);
  EXPECT_EQ(self_dot, 14); // 1*1 + 2*2 + 3*3 = 1 + 4 + 9 = 14

  // Test dot product with zero vector
  Vec3<int> zero_vec = {0, 0, 0};
  EXPECT_EQ(int_vec1.dot(zero_vec), 0);
}

// Test cross product
TEST_F(Vec3Test, CrossProduct) {
  // Test integer cross product
  auto int_cross = int_vec1.cross(int_vec2);
  EXPECT_EQ(int_cross.x, -3); // (2*6 - 3*5) = 12 - 15 = -3
  EXPECT_EQ(int_cross.y, 6);  // (3*4 - 1*6) = 12 - 6 = 6
  EXPECT_EQ(int_cross.z, -3); // (1*5 - 2*4) = 5 - 8 = -3

  // Test float cross product
  auto float_cross = float_vec1.cross(float_vec2);
  EXPECT_FLOAT_EQ(float_cross.x,
                  -3.0f); // (2.5*6.5 - 3.5*5.5) = 16.25 - 19.25 = -3
  EXPECT_FLOAT_EQ(float_cross.y,
                  6.0f); // (3.5*4.5 - 1.5*6.5) = 15.75 - 9.75 = 6
  EXPECT_FLOAT_EQ(float_cross.z,
                  -3.0f); // (1.5*5.5 - 2.5*4.5) = 8.25 - 11.25 = -3

  // Test double cross product
  auto double_cross = double_vec1.cross(double_vec2);
  EXPECT_DOUBLE_EQ(double_cross.x, -3.0);
  EXPECT_DOUBLE_EQ(double_cross.y, 6.0);
  EXPECT_DOUBLE_EQ(double_cross.z, -3.0);

  // Test cross product with self (should be zero)
  auto self_cross = int_vec1.cross(int_vec1);
  EXPECT_EQ(self_cross.x, 0);
  EXPECT_EQ(self_cross.y, 0);
  EXPECT_EQ(self_cross.z, 0);

  // Test cross product of standard basis vectors (i × j = k)
  Vec3<int> vec_i = {1, 0, 0};
  Vec3<int> vec_j = {0, 1, 0};
  Vec3<int> vec_k = {0, 0, 1};

  auto i_cross_j = vec_i.cross(vec_j);
  EXPECT_EQ(i_cross_j.x, 0);
  EXPECT_EQ(i_cross_j.y, 0);
  EXPECT_EQ(i_cross_j.z, 1);

  auto j_cross_k = vec_j.cross(vec_k);
  EXPECT_EQ(j_cross_k.x, 1);
  EXPECT_EQ(j_cross_k.y, 0);
  EXPECT_EQ(j_cross_k.z, 0);

  auto k_cross_i = vec_k.cross(vec_i);
  EXPECT_EQ(k_cross_i.x, 0);
  EXPECT_EQ(k_cross_i.y, 1);
  EXPECT_EQ(k_cross_i.z, 0);
}

// Test with edge cases
TEST_F(Vec3Test, EdgeCases) {
  // Test with max values
  Vec3<int> max_vec = {std::numeric_limits<int>::max(),
                       std::numeric_limits<int>::max(),
                       std::numeric_limits<int>::max()};

  // Addition with max values may overflow, but we want to test the operation
  // works
  auto max_addition = max_vec + int_vec1;

  // Test with min values
  Vec3<int> min_vec = {std::numeric_limits<int>::min(),
                       std::numeric_limits<int>::min(),
                       std::numeric_limits<int>::min()};

  // Subtraction with min values may underflow, but we want to test the
  // operation works
  auto min_subtraction = min_vec - int_vec1;

  // Test with mixed values
  Vec3<double> mixed_vec1 = {0.0, -1.0,
                             std::numeric_limits<double>::infinity()};
  Vec3<double> mixed_vec2 = {-0.0, 1.0,
                             -std::numeric_limits<double>::infinity()};

  auto mixed_addition = mixed_vec1 + mixed_vec2;
  // 0.0 + (-0.0) = 0.0
  EXPECT_DOUBLE_EQ(mixed_addition.x, 0.0);
  // -1.0 + 1.0 = 0.0
  EXPECT_DOUBLE_EQ(mixed_addition.y, 0.0);
  // inf + (-inf) = NaN
  EXPECT_TRUE(std::isnan(mixed_addition.z));

  // Test with NaN
  Vec3<double> nan_vec = {std::numeric_limits<double>::quiet_NaN(),
                          std::numeric_limits<double>::quiet_NaN(),
                          std::numeric_limits<double>::quiet_NaN()};

  // Any operation with NaN should result in NaN
  auto nan_result = double_vec1 + nan_vec;
  EXPECT_TRUE(std::isnan(nan_result.x));
  EXPECT_TRUE(std::isnan(nan_result.y));
  EXPECT_TRUE(std::isnan(nan_result.z));
}

// Test squared_norm2 and norm2 methods
TEST_F(Vec3Test, NormMethods) {
  // Test squared_norm2 for integer vector
  EXPECT_DOUBLE_EQ(int_vec1.squared_norm2(), 14.0); // 1*1 + 2*2 + 3*3 = 14

  // Test norm2 for integer vector
  EXPECT_DOUBLE_EQ(int_vec1.norm2(), std::sqrt(14.0)); // √14 ≈ 3.741657...

  // Test squared_norm2 for float vector
  EXPECT_DOUBLE_EQ(
      float_vec1.squared_norm2(),
      20.75); // 1.5*1.5 + 2.5*2.5 + 3.5*3.5 = 2.25 + 6.25 + 12.25 = 20.75

  // Test norm2 for float vector
  EXPECT_DOUBLE_EQ(float_vec1.norm2(), std::sqrt(20.75)); // √20.75 ≈ 4.5552...

  // Test squared_norm2 for double vector
  EXPECT_DOUBLE_EQ(double_vec1.squared_norm2(),
                   20.75); // Same as float calculation

  // Test norm2 for double vector
  EXPECT_DOUBLE_EQ(double_vec1.norm2(), std::sqrt(20.75));

  // Test with zero vector
  Vec3<int> zero_vec = {0, 0, 0};
  EXPECT_DOUBLE_EQ(zero_vec.squared_norm2(), 0.0);
  EXPECT_DOUBLE_EQ(zero_vec.norm2(), 0.0);

  // Test with unit vectors
  Vec3<double> unit_x = {1.0, 0.0, 0.0};
  Vec3<double> unit_y = {0.0, 1.0, 0.0};
  Vec3<double> unit_z = {0.0, 0.0, 1.0};

  EXPECT_DOUBLE_EQ(unit_x.squared_norm2(), 1.0);
  EXPECT_DOUBLE_EQ(unit_x.norm2(), 1.0);

  EXPECT_DOUBLE_EQ(unit_y.squared_norm2(), 1.0);
  EXPECT_DOUBLE_EQ(unit_y.norm2(), 1.0);

  EXPECT_DOUBLE_EQ(unit_z.squared_norm2(), 1.0);
  EXPECT_DOUBLE_EQ(unit_z.norm2(), 1.0);

  // Test with negative components
  Vec3<int> neg_vec = {-1, -2, -3};
  EXPECT_DOUBLE_EQ(neg_vec.squared_norm2(), 14.0); // (-1)² + (-2)² + (-3)² = 14
  EXPECT_DOUBLE_EQ(neg_vec.norm2(), std::sqrt(14.0));
}

// Test norm methods with special values
TEST_F(Vec3Test, NormEdgeCases) {
  // Test with infinity
  Vec3<double> inf_vec = {std::numeric_limits<double>::infinity(), 0.0, 0.0};
  EXPECT_TRUE(std::isinf(inf_vec.squared_norm2()));
  EXPECT_TRUE(std::isinf(inf_vec.norm2()));

  // Test with large values that might cause overflow in intermediate
  // calculations
  double large_val = std::sqrt(std::numeric_limits<double>::max()) / 2.0;
  Vec3<double> large_vec = {large_val, large_val, large_val};

  // The squared norm should be approximately 3 * large_val²
  double expected_squared = 3.0 * large_val * large_val;
  EXPECT_DOUBLE_EQ(large_vec.squared_norm2(), expected_squared);

  // The norm should be √(3) * large_val
  double expected_norm = std::sqrt(3.0) * large_val;
  EXPECT_DOUBLE_EQ(large_vec.norm2(), expected_norm);

  // Test with NaN values
  Vec3<double> nan_vec = {std::numeric_limits<double>::quiet_NaN(), 0.0, 0.0};
  EXPECT_TRUE(std::isnan(nan_vec.squared_norm2()));
  EXPECT_TRUE(std::isnan(nan_vec.norm2()));
}

// Main function that runs the tests
int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}