text: #include "src/lib/solution.h"
  #include "gtest/gtest.h"
  #include <vector>
  
  TEST(Add, Return) {
    Solution solution;
    int a = 599;
    int b = 1;
    std::string aa = "ee";
    std::string bb = "EE";
  
    int actual1 = solution.Add(a,b);
    int expected1 = a+b;
  
    std::string actual2 = solution.Add(aa,bb);
    std::string expected2 = "eeEE";
  
    std::string actual3 = solution.Add(bb,a);
    std::string expected3 = "EE599";
  
    std::string actual4 = solution.Add(b,aa);
    std::string expected4 = "1ee";
    EXPECT_EQ(expected1, actual1);
    EXPECT_EQ(expected2, actual2);
    EXPECT_EQ(expected3, actual3);
    EXPECT_EQ(expected4, actual4);
  }