int main(int argc, char* argv[]) {
FileSystem fs;
// should print ""
cout << join(fs.Ls("/")) << endl;
fs.MkdirP("/a/b/c");
fs.MkdirP("/a/b/e");
fs.AddFileWithContent("/a/b/c/d", "hello world");
// should print a
cout << join(fs.Ls("/")) << endl;
// should print c,e
cout << join(fs.Ls("/a/b")) << endl;
// should print d
cout << join(fs.Ls("/a/b/c")) << endl;
// should print d
cout << join(fs.Ls("/a/b/c/d")) << endl;
// should print hello world
cout << fs.GetFileContent("/a/b/c/d");
cout<<endl;
}
