module Unix::Group

def group_absent(name, &block)
  execute("if getent group #{name}; then groupdel #{name}; fi", {}, &block)
end

def group_get(name)
  execute("getent group #{name}") do |result|
    fail_test "failed to get group #{name}" unless /^#{name}:.*:[0-9]+:/.match?(result.stdout)
    yield result if block_given?
    result
  end
end

def group_gid(name)
  execute("getent group #{name}") do |result|
    # Format is:
    # wheel:x:10:root
    result.stdout.split(':')[2]
  end
end

def group_list
  execute("getent group") do |result|
    groups = []
    result.stdout.each_line do |line|
      groups << (line.match(/^([^:]+)/) or next)[1]
    end
    yield result if block_given?
    groups
  end
end

def group_present(name, &block)
  execute("if ! getent group #{name}; then groupadd #{name}; fi", {}, &block)
end