class FakeFS::Pathname

manipulation.
This method doesn't access the file system; it is pure string

p3 = p1 + "/etc/passwd" # Pathname:/etc/passwd
p2 = p1 + "bin/ruby" # Pathname:/usr/bin/ruby
p1 = Pathname.new("/usr") # Pathname:/usr

object.
Pathname
Pathname#+ appends a pathname fragment to this one to produce a new

def +(other)
  other = Pathname.new(other) unless other.is_a?(Pathname)
  Pathname.new(plus(@path, other.to_s))
end