text: //Unit Tests for MPAGSCipher transformChar interface
  #define CATCH_CONFIG_MAIN
  #include "catch.hpp"
  
  #include "TransformChar.hpp"
  
  TEST_CASE("Characters are uppercased", "[alphanumeric]"){
    const std::string upper{"ABCDEFGHIJKLMNOPQRSTUVWXYZ"};
    const std::string lower{"abcdefghijklmnopqrstuvwxyz"};
  
    for (size_t i = 0; i< upper.size(); i++){
      REQUIRE( transformChar(lower[i]) == std::string{upper[i]} );
    }
  
  }
  
  TEST_CASE("Digits are transliterated", "[alphanumeric]"){
    REQUIRE( transformChar('0') == "ZERO" );
    REQUIRE( transformChar('1') == "ONE" );
    REQUIRE( transformChar('2') == "TWO");
    REQUIRE( transformChar('3') == "THREE");
    REQUIRE( transformChar('4') == "FOUR");
    REQUIRE( transformChar('5') == "FIVE");
    REQUIRE( transformChar('6') == "SIX");
    REQUIRE( transformChar('7') == "SEVEN");
    REQUIRE( transformChar('8') == "EIGHT");
    REQUIRE( transformChar('9') == "NINE");
  }
  
  TEST_CASE("Non-alphanumeric input handled correctly", "[alphanumeric]"){
    REQUIRE( transformChar('!') == "");
  }
  