argparse/test/test_help.cpp

#include <argparse/argparse.hpp>
#include <doctest.hpp>
#include <regex>
#include <sstream>
#include <unordered_map>

using doctest::test_suite;

TEST_CASE("Users can format help message" * test_suite("help")) {
  argparse::ArgumentParser program("test");

  SUBCASE("Simple arguments") {
    program.add_argument("input").help("positional input");
    program.add_argument("-c").help("optional input");
  }
  SUBCASE("Default values") {
    program.add_argument("-a").default_value(42);
    program.add_argument("-b").default_value(4.4e-7);
    program.add_argument("-c")
        .default_value(std::vector<int>{1, 2, 3, 4, 5})
        .nargs(5);
    program.add_argument("-d").default_value("I am a string");
    program.add_argument("-e").default_value(std::optional<float>{});
    program.add_argument("-f").default_value(false);
  }
  std::ostringstream s;
  s << program;
  REQUIRE_FALSE(s.str().empty());

  auto msg = program.help().str();
  REQUIRE(msg == s.str());
}

TEST_CASE("Users can override the help options" * test_suite("help")) {
  GIVEN("a program that meant to take -h as a normal option") {
    argparse::ArgumentParser program("test");
    program.add_argument("input");
    program.add_argument("-h").implicit_value('h').default_value('x');

    WHEN("provided -h without fulfilling other requirements") {
      THEN("validation fails") {
        REQUIRE_THROWS_AS(program.parse_args({"test", "-h"}),
                          std::runtime_error);
      }
    }

    WHEN("provided arguments to all parameters") {
      program.parse_args({"test", "-h", "some input"});

      THEN("these parameters get their values") {
        REQUIRE(program["-h"] == 'h');
        REQUIRE(program.get("input") == "some input");
      }
    }
  }
}

TEST_CASE("Users can disable default -h/--help" * test_suite("help")) {
  argparse::ArgumentParser program("test", "1.0",
                                   argparse::default_arguments::version);
  REQUIRE_THROWS_AS(program.parse_args({"test", "-h"}), std::runtime_error);
}

TEST_CASE("Users can replace default -h/--help" * test_suite("help")) {
  argparse::ArgumentParser program("test", "1.0",
                                   argparse::default_arguments::version);
  std::stringstream buffer;
  program.add_argument("-h", "--help")
      .action([&](const auto &) { buffer << program; })
      .default_value(false)
      .implicit_value(true)
      .nargs(0);

  REQUIRE(buffer.str().empty());
  program.parse_args({"test", "--help"});
  REQUIRE_FALSE(buffer.str().empty());
}

TEST_CASE("Multiline help message alignment") {
  argparse::ArgumentParser program("program");
  program.add_argument("input1")
      .help(
        "This is the first line of help message.\n"
        "And this is the second line of help message."
      );
  program.add_argument("program_input2")
      .help("There is only one line.");
  program.add_argument("-p", "--prog_input3")
      .help(
R"(Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed ut perspiciatis unde omnis iste natus error sit voluptatem
accusantium doloremque laudantium, totam rem aperiam...)"
      );

  std::ostringstream stream;
  stream << program;
  std::string help_text = stream.str();

  // Split the help text into lines
  std::istringstream iss(help_text);
  std::vector<std::string> help_lines;
  std::string line;
  while (std::getline(iss, line)) {
    help_lines.push_back(line);
  }

  // A map to store the starting position of the help text for each argument
  std::unordered_map<std::string, int> help_start_positions;

  for (const auto& line : help_lines) {
    // Find the argument names in the line
    std::smatch match;
    if (std::regex_search(line, match, std::regex(R"((input1|program_input2|--prog_input3))"))) {
      std::string arg_name = match.str();

      // Find the position of the first non-space character after the argument name
      int position = line.find_first_not_of(' ', match.position() + arg_name.size());
      if (position == std::string::npos) {
        continue;
      }
      help_start_positions[arg_name] = position;
    }
  }

  // Check if the positions are the same for all arguments
  REQUIRE(!help_start_positions.empty());
  int first_position = help_start_positions.begin()->second;
  for (const auto& entry : help_start_positions) {
    REQUIRE(entry.second == first_position);
  }
}