Unit Testing Boost filesystem create_directories

Question

I want to unit test the boost filesystem function create_directories() for it's failure case, i.e., when create_directory fails. Can someone please provide any suggestions on how to do this? Another requirement is that the code needs to be cross-platform.

Answer 1

You could try to create a directory in a path to a file:

#include <fstream>
#include <iostream>
#include "boost/filesystem/path.hpp"
#include "boost/filesystem/operations.hpp"

namespace bfs = boost::filesystem;

int main() {
  // Create test dir
  boost::system::error_code ec;
  bfs::path test_root(bfs::unique_path(
      bfs::temp_directory_path(ec) / "%%%%-%%%%-%%%%"));
  if (!bfs::create_directory(test_root, ec) || ec) {
    std::cout << "Failed creating " << test_root << ": " << ec.message() << '\n';
    return -1;
  }

  // Create file in test dir
  bfs::path test_file(test_root / "file");
  std::ofstream file_out(test_file.c_str());
  file_out.close();
  if (!bfs::exists(test_file, ec)) {
    std::cout << "Failed creating " << test_file << ": " << ec.message() << '\n';
    return -2;
  }

  // Try to create directory in test_file - should fail
  bfs::path invalid_dir(test_file / "dir");
  if (bfs::create_directory(invalid_dir, ec)) {
    std::cout << "Succeeded creating invalid dir " << invalid_dir << '\n';
    return -3;
  }

  // Try to create nested directory in test_file - should fail
  bfs::path nested_invalid_dir(invalid_dir / "nested_dir");
  if (bfs::create_directories(nested_invalid_dir, ec)) {
    std::cout << "Succeeded creating nested invalid dir " << invalid_dir << '\n';
    return -4;
  }

  // Clean up
  bfs::remove_all(test_root);
  return 0;
}