Use Util::Tempfile when configuring networks

This fixes a fairly large tempfile leak. Vagrant uses a template
renderer to write network configuration files locally to disk. Then,
that temporarily file is uploaded to the remote host and moved into
place. Since Vagrant is such a short-lived process, GC never came along
and cleaned up those tempfiles, resulting in many temporary files being
created through regular Vagrant usage.

The Util::Tempfile class uses a block to ensure the temporary file is
deleted when the block finishes. This API required small tweaks to the
usage, but provides more safety to ensure the files are deleted.

plugins/communicators/winrm/communicator.rb

@@ -5,11 +5,14 @@ require "log4r"
 require_relative "helper"
 require_relative "shell"
 require_relative "command_filter"
+require_relative "../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module CommunicatorWinRM
     # Provides communication channel for Vagrant commands via WinRM.
     class Communicator < Vagrant.plugin("2", :communicator)
+      include Vagrant::Util
+
       def self.match?(machine)
         # This is useless, and will likely be removed in the future (this
         # whole method).
@@ -202,15 +205,11 @@ module VagrantPlugins
           interactive: interactive,
         })
         guest_script_path = "c:/tmp/vagrant-elevated-shell.ps1"
-        file = Tempfile.new(["vagrant-elevated-shell", "ps1"])
+        Tempfile.create(["vagrant-elevated-shell", "ps1"]) do |f|
-        begin
+          f.write(script)
-          file.write(script)
+          f.fsync
-          file.fsync
+          f.close
-          file.close
+          upload(f.path, guest_script_path)
-          upload(file.path, guest_script_path)
-        ensure
-          file.close
-          file.unlink
         end
 
         # Convert to double byte unicode string then base64 encode

plugins/guests/arch/cap/configure_networks.rb

@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestArch
@@ -10,23 +9,29 @@ module VagrantPlugins
         include Vagrant::Util
 
         def self.configure_networks(machine, networks)
-          interfaces = Array.new
+          tempfiles  = []
+          interfaces = []
+
           machine.communicate.sudo("ip -o -0 addr | grep -v LOOPBACK | awk '{print $2}' | sed 's/://'") do |_, result|
             interfaces = result.split("\n")
           end
 
-          networks.each do |network|
+          networks.each.with_index do |network, i|
             network[:device] = interfaces[network[:interface]]
 
-            entry = TemplateRenderer.render("guests/arch/network_#{network[:type]}", options: network)
+            entry = TemplateRenderer.render("guests/arch/network_#{network[:type]}",
+              options: network)
 
-            temp = Tempfile.new("vagrant")
+            remote_path = "/tmp/vagrant-network-#{Time.now.to_i}-#{i}"
-            temp.binmode
-            temp.write(entry)
-            temp.close
 
-            machine.communicate.upload(temp.path, "/tmp/vagrant_network")
+            Tempfile.create("arch-configure-networks") do |f|
-            machine.communicate.sudo("mv /tmp/vagrant_network /etc/netctl/#{network[:device]}")
+              f.write(entry)
+              f.fsync
+              f.close
+              machine.communicate.upload(f.path, remote_path)
+            end
+
+            machine.communicate.sudo("mv #{remote_path} /etc/netctl/#{network[:device]}")
             machine.communicate.sudo("ip link set #{network[:device]} down && netctl restart #{network[:device]} && netctl enable #{network[:device]}")
           end
         end

plugins/guests/coreos/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestCoreOS
@@ -54,11 +53,11 @@ module VagrantPlugins
               })
             end
 
-            Tempfile.open("vagrant") do |temp|
+            Tempfile.create("coreos-configure-networks") do |f|
-              temp.binmode
+              f.write(entry)
-              temp.write(entry)
+              f.fsync
-              temp.close
+              f.close
-              comm.upload(temp.path, "/tmp/etcd-cluster.service")
+              comm.upload(f.path, "/tmp/etcd-cluster.service")
             end
 
             comm.sudo("mv /tmp/etcd-cluster.service /media/state/units/")

plugins/guests/debian/cap/configure_networks.rb

@@ -1,7 +1,7 @@
-require 'set'
+require "set"
-require 'tempfile'
 
-require "vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module GuestDebian
@@ -29,14 +29,14 @@ module VagrantPlugins
               entries << entry
             end
 
-            # Perform the careful dance necessary to reconfigure
+            # Perform the careful dance necessary to reconfigure the network
-            # the network interfaces
+            # interfaces.
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("debian-configure-networks") do |f|
-            temp.binmode
+              f.write(entries.join("\n"))
-            temp.write(entries.join("\n"))
+              f.fsync
-            temp.close
+              f.close
-
+              comm.upload(f.path, "/tmp/vagrant-network-entry")
-            comm.upload(temp.path, "/tmp/vagrant-network-entry")
+            end
 
             # Bring down all the interfaces we're reconfiguring. By bringing down
             # each specifically, we avoid reconfiguring eth0 (the NAT interface) so

plugins/guests/fedora/cap/configure_networks.rb

@@ -1,8 +1,8 @@
 require "set"
-require "tempfile"
 
-require "vagrant/util/retryable"
+require_relative "../../../../lib/vagrant/util/retryable"
-require "vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module GuestFedora
@@ -96,12 +96,12 @@ module VagrantPlugins
             entry = TemplateRenderer.render("guests/fedora/network_#{network[:type]}",
                                             options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("fedora-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
-
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry_#{interface}")
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry_#{interface}")
+            end
           end
 
           # Bring down all the interfaces we're reconfiguring. By bringing down

plugins/guests/freebsd/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestFreeBSD
@@ -29,13 +28,13 @@ module VagrantPlugins
             entry  = TemplateRenderer.render("guests/freebsd/network_#{network[:type]}",
                                             options: network, ifname: ifname)
 
-            # Write the entry to a temporary location
+            Tempfile.create("freebsd-configure-networks") do |f|
-            temp = Tempfile.new("vagrant")
+              f.write(entry)
-            temp.binmode
+              f.fsync
-            temp.write(entry)
+              f.close
-            temp.close
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry")
+            end
 
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry")
             machine.communicate.sudo("su -m root -c 'cat /tmp/vagrant-network-entry >> /etc/rc.conf'", {shell: "sh"})
             machine.communicate.sudo("rm -f /tmp/vagrant-network-entry", {shell: "sh"})
 

plugins/guests/funtoo/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestFuntoo
@@ -23,12 +22,15 @@ module VagrantPlugins
                 ifFile = "netif.eth#{network[:interface]}"
                 entry = TemplateRenderer.render("guests/funtoo/network_#{network[:type]}",
                                                  options: network)
+
                 # Upload the entry to a temporary location
-                temp = Tempfile.new("vagrant")
+                Tempfile.create("funtoo-configure-networks") do |f|
-                temp.binmode
+                  f.write(entry)
-                temp.write(entry)
+                  f.fsync
-                temp.close
+                  f.close
-                comm.upload(temp.path, "/tmp/vagrant-#{ifFile}")
+                  comm.upload(f.path, "/tmp/vagrant-#{ifFile}")
+                end
+
                 comm.sudo("cp /tmp/vagrant-#{ifFile} /etc/conf.d/#{ifFile}")
                 comm.sudo("chmod 0644 /etc/conf.d/#{ifFile}")
                 comm.sudo("ln -fs /etc/init.d/netif.tmpl /etc/init.d/#{ifFile}")

plugins/guests/gentoo/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestGentoo
@@ -21,12 +20,12 @@ module VagrantPlugins
                                               options: network)
 
               # Upload the entry to a temporary location
-              temp = Tempfile.new("vagrant")
+              Tempfile.create("gentoo-configure-networks") do |f|
-              temp.binmode
+                f.write(entry)
-              temp.write(entry)
+                f.fsync
-              temp.close
+                f.close
-
+                comm.upload(f.path, "/tmp/vagrant-network-entry")
-              comm.upload(temp.path, "/tmp/vagrant-network-entry")
+              end
 
               # Configure the interface
               comm.sudo("ln -fs /etc/init.d/net.lo /etc/init.d/net.eth#{network[:interface]}")

plugins/guests/netbsd/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestNetBSD
@@ -20,13 +19,13 @@ module VagrantPlugins
             entry = TemplateRenderer.render("guests/netbsd/network_#{network[:type]}",
                                             options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("netbsd-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry")
+            end
 
-            # upload it and append it to the new rc.conf file
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry")
             machine.communicate.sudo("cat /tmp/vagrant-network-entry >> #{newrcconf}")
             machine.communicate.sudo("rm -f /tmp/vagrant-network-entry")
 
@@ -45,7 +44,6 @@ module VagrantPlugins
 
           # install new rc.conf
           machine.communicate.sudo("install -c -o 0 -g 0 -m 644 #{newrcconf} /etc/rc.conf")
-
         end
       end
     end

plugins/guests/nixos/cap/change_host_name.rb

@@ -1,6 +1,5 @@
-require 'tempfile'
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestNixos
@@ -16,13 +15,15 @@ module VagrantPlugins
 
         # Upload a file.
         def self.upload(machine, content, remote_path)
-          local_temp = Tempfile.new("vagrant-upload")
-          local_temp.binmode
-          local_temp.write(content)
-          local_temp.close
           remote_temp = mktemp(machine)
-          machine.communicate.upload(local_temp.path, "#{remote_temp}")
+
-          local_temp.delete
+          Tempfile.create("nixos-change-host-name") do |f|
+            f.write(content)
+            f.fsync
+            f.close
+            machine.communicate.upload(f.path, "#{remote_temp}")
+          end
+
           machine.communicate.sudo("mv #{remote_temp} #{remote_path}")
         end
 

plugins/guests/nixos/cap/configure_networks.rb

@@ -1,7 +1,7 @@
-require 'tempfile'
+require "ipaddr"
-require 'ipaddr'
 
-require "vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module GuestNixos
@@ -65,13 +65,15 @@ module VagrantPlugins
 
         # Upload a file.
         def self.upload(machine, content, remote_path)
-          local_temp = Tempfile.new("vagrant-upload")
-          local_temp.binmode
-          local_temp.write(content)
-          local_temp.close
           remote_temp = mktemp(machine)
-          machine.communicate.upload(local_temp.path, "#{remote_temp}")
+
-          local_temp.delete
+          Tempfile.create("nixos-configure-networks") do |f|
+            f.write(content)
+            f.fsync
+            f.close
+            machine.communicate.upload(f.path, "#{remote_temp}")
+          end
+
           machine.communicate.sudo("mv #{remote_temp} #{remote_path}")
         end
 

plugins/guests/openbsd/cap/configure_networks.rb

@@ -1,6 +1,5 @@
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestOpenBSD
@@ -13,10 +12,12 @@ module VagrantPlugins
             entry = TemplateRenderer.render("guests/openbsd/network_#{network[:type]}",
                                             options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("openbsd-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry")
+            end
 
             # Determine the interface prefix...
             command = "ifconfig -a | grep -o ^[0-9a-z]*"
@@ -31,7 +32,6 @@ module VagrantPlugins
               end
             end
 
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry")
             machine.communicate.sudo("mv /tmp/vagrant-network-entry /etc/hostname.#{ifname}")
 
             # remove old configurations

plugins/guests/redhat/cap/configure_networks.rb

@@ -1,8 +1,8 @@
 require "set"
-require "tempfile"
 
-require "vagrant/util/retryable"
+require_relative "../../../../lib/vagrant/util/retryable"
-require "vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module GuestRedHat
@@ -55,12 +55,12 @@ module VagrantPlugins
             entry = TemplateRenderer.render("guests/redhat/network_#{network[:type]}",
                                             options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("red-hat-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
-
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry_#{network[:interface]}")
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry_#{network[:interface]}")
+            end
           end
 
           # Bring down all the interfaces we're reconfiguring. By bringing down

plugins/guests/slackware/cap/configure_networks.rb

@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
-require "tempfile"
+require_relative "../../../../lib/vagrant/util/template_renderer"
-
+require_relative "../../../../lib/vagrant/util/tempfile"
-require "vagrant/util/template_renderer"
 
 module VagrantPlugins
   module GuestSlackware
@@ -20,12 +19,13 @@ module VagrantPlugins
 
             entry = TemplateRenderer.render("guests/slackware/network_#{network[:type]}", options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("slackware-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
+              machine.communicate.upload(f.path, "/tmp/vagrant_network")
+            end
 
-            machine.communicate.upload(temp.path, "/tmp/vagrant_network")
             machine.communicate.sudo("mv /tmp/vagrant_network /etc/rc.d/rc.inet1.conf")
             machine.communicate.sudo("/etc/rc.d/rc.inet1")
           end

plugins/guests/suse/cap/configure_networks.rb

@@ -1,8 +1,8 @@
 require "set"
-require "tempfile"
 
-require "vagrant/util/retryable"
+require_relative "../../../../lib/vagrant/util/retryable"
-require "vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/template_renderer"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module GuestSUSE
@@ -33,12 +33,12 @@ module VagrantPlugins
             entry = TemplateRenderer.render("guests/suse/network_#{network[:type]}",
                                             options: network)
 
-            temp = Tempfile.new("vagrant")
+            Tempfile.create("suse-configure-networks") do |f|
-            temp.binmode
+              f.write(entry)
-            temp.write(entry)
+              f.fsync
-            temp.close
+              f.close
-
+              machine.communicate.upload(f.path, "/tmp/vagrant-network-entry_#{network[:interface]}")
-            machine.communicate.upload(temp.path, "/tmp/vagrant-network-entry_#{network[:interface]}")
+            end
           end
 
           # Bring down all the interfaces we're reconfiguring. By bringing down

plugins/provisioners/ansible/provisioner/guest.rb

@@ -1,11 +1,11 @@
-require 'tempfile'
-
 require_relative "base"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module Ansible
     module Provisioner
       class Guest < Base
+        include Vagrant::Util
 
         def initialize(machine, config)
           super
@@ -103,14 +103,14 @@ module VagrantPlugins
           inventory_basedir = File.join(config.tmp_path, "inventory")
           inventory_path = File.join(inventory_basedir, "vagrant_ansible_local_inventory")
 
-          temp_inventory = Tempfile.new("vagrant_ansible_local_inventory_#{@machine.name}")
-          temp_inventory.write(inventory_content)
-          temp_inventory.close
-
           create_and_chown_remote_folder(inventory_basedir)
-          @machine.communicate.tap do |comm|
+          @machine.communicate.sudo("rm -f #{inventory_path}", error_check: false)
-            comm.sudo("rm -f #{inventory_path}", error_check: false)
+
-            comm.upload(temp_inventory.path, inventory_path)
+          Tempfile.create("ansible-local-inventory-#{@machine.name}") do |f|
+            f.write(inventory_content)
+            f.fsync
+            f.close
+            @machine.communicate.upload(f.path, inventory_path)
           end
 
           return inventory_basedir

plugins/provisioners/chef/provisioner/chef_apply.rb

@@ -1,7 +1,7 @@
 require "digest/md5"
-require "tempfile"
 
 require_relative "base"
+require_relative "../../../../lib/vagrant/util/tempfile"
 
 module VagrantPlugins
   module Chef
@@ -54,17 +54,15 @@ module VagrantPlugins
         # Write the raw recipe contents to a tempfile and upload that to the
         # machine.
         def upload_recipe
-          # Write the raw recipe contents to a tempfile
+          # Write the raw recipe contents to a tempfile and upload
-          file = Tempfile.new(["vagrant-chef-apply", ".rb"])
+          Tempfile.create(["chef-apply", ".rb"]) do |f|
-          file.write(config.recipe)
+            f.write(config.recipe)
-          file.rewind
+            f.fsync
+            f.close
 
             # Upload the tempfile to the guest
-          @machine.communicate.upload(file.path, target_recipe_path)
+            @machine.communicate.upload(f.path, target_recipe_path)
-        ensure
+          end
-          # Delete our template
-          file.close
-          file.unlink
         end
       end
     end

test/unit/plugins/guests/arch/cap/change_host_name_test.rb

@@ -0,0 +1,37 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestArch::Cap::ChangeHostName" do
+  let(:described_class) do
+    VagrantPlugins::GuestArch::Plugin
+      .components
+      .guest_capabilities[:arch]
+      .get(:change_host_name)
+  end
+
+  let(:machine) { double("machine") }
+  let(:communicator) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(communicator)
+  end
+
+  after do
+    communicator.verify_expectations!
+  end
+
+  describe ".change_host_name" do
+    let(:hostname) { "example.com" }
+
+    it "sets the hostname" do
+      communicator.stub_command("sudo hostname | grep '#{hostname}'", exit_code: 1)
+      communicator.expect_command("hostnamectl set-hostname #{hostname}")
+      described_class.change_host_name(machine, hostname)
+    end
+
+    it "does not change the hostname if already set" do
+      communicator.stub_command("sudo hostname | grep '#{hostname}'", exit_code: 0)
+      described_class.change_host_name(machine, hostname)
+      expect(communicator.received_commands.size).to eq(1)
+    end
+  end
+end

test/unit/plugins/guests/arch/cap/configure_networks_test.rb

@@ -0,0 +1,48 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestArch::Cap::ConfigureNetworks" do
+  let(:described_class) do
+    VagrantPlugins::GuestArch::Plugin
+      .components
+      .guest_capabilities[:arch]
+      .get(:configure_networks)
+  end
+
+  let(:machine) { double("machine") }
+  let(:communicator) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(communicator)
+    communicator.stub_command("ip -o -0 addr | grep -v LOOPBACK | awk '{print $2}' | sed 's/://'",
+      stdout: "eth1\neth2")
+  end
+
+  after do
+    communicator.verify_expectations!
+  end
+
+  describe ".configure_networks" do
+    let(:network_1) do
+      {
+        interface: 0,
+        type: "dhcp",
+      }
+    end
+
+    let(:network_2) do
+      {
+        interface: 1,
+        type: "static",
+        ip: "33.33.33.10",
+        netmask: "255.255.0.0",
+        gateway: "33.33.0.1",
+      }
+    end
+
+    it "creates and starts the networks" do
+      communicator.expect_command("ip link set eth1 down && netctl restart eth1 && netctl enable eth1")
+      communicator.expect_command("ip link set eth2 down && netctl restart eth2 && netctl enable eth2")
+      described_class.configure_networks(machine, [network_1, network_2])
+    end
+  end
+end

test/unit/plugins/guests/coreos/cap/change_host_name_test.rb

@@ -0,0 +1,37 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestCoreOS::Cap::ChangeHostName" do
+  let(:described_class) do
+    VagrantPlugins::GuestCoreOS::Plugin
+      .components
+      .guest_capabilities[:coreos]
+      .get(:change_host_name)
+  end
+
+  let(:machine) { double("machine") }
+  let(:communicator) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(communicator)
+  end
+
+  after do
+    communicator.verify_expectations!
+  end
+
+  describe ".change_host_name" do
+    let(:hostname) { "example.com" }
+
+    it "sets the hostname" do
+      communicator.stub_command("sudo hostname --fqdn | grep '#{hostname}'", exit_code: 1)
+      communicator.expect_command("hostname example")
+      described_class.change_host_name(machine, hostname)
+    end
+
+    it "does not change the hostname if already set" do
+      communicator.stub_command("sudo hostname --fqdn | grep '#{hostname}'", exit_code: 0)
+      described_class.change_host_name(machine, hostname)
+      expect(communicator.received_commands.size).to eq(1)
+    end
+  end
+end

test/unit/plugins/guests/debian/cap/change_host_name_test.rb

@@ -1,10 +1,14 @@
-require File.expand_path("../../../../../base", __FILE__)
+require_relative "../../../../base"
-require File.expand_path("../../../support/shared/debian_like_host_name_examples", __FILE__)
+require_relative "../../support/shared/debian_like_host_name_examples"
 
 describe "VagrantPlugins::GuestDebian::Cap::ChangeHostName" do
   let(:described_class) do
-    VagrantPlugins::GuestDebian::Plugin.components.guest_capabilities[:debian].get(:change_host_name)
+    VagrantPlugins::GuestDebian::Plugin
+      .components
+      .guest_capabilities[:debian]
+      .get(:change_host_name)
   end
+
   let(:machine) { double("machine") }
   let(:communicator) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
   let(:old_hostname) { 'oldhostname.olddomain.tld' }

test/unit/plugins/guests/debian/cap/configure_networks_test.rb

@@ -0,0 +1,50 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestDebian::Cap::ConfigureNetworks" do
+  let(:described_class) do
+    VagrantPlugins::GuestDebian::Plugin
+      .components
+      .guest_capabilities[:debian]
+      .get(:configure_networks)
+  end
+
+  let(:machine) { double("machine") }
+  let(:communicator) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(communicator)
+  end
+
+  after do
+    communicator.verify_expectations!
+  end
+
+  describe ".configure_networks" do
+    let(:network_0) do
+      {
+        interface: 0,
+        type: "dhcp",
+      }
+    end
+
+    let(:network_1) do
+      {
+        interface: 1,
+        type: "static",
+        ip: "33.33.33.10",
+        netmask: "255.255.0.0",
+        gateway: "33.33.0.1",
+      }
+    end
+
+    it "creates and starts the networks" do
+      communicator.expect_command("/sbin/ifdown eth0 2> /dev/null || true")
+      communicator.expect_command("/sbin/ip addr flush dev eth0 2> /dev/null")
+      communicator.expect_command("/sbin/ifdown eth1 2> /dev/null || true")
+      communicator.expect_command("/sbin/ip addr flush dev eth1 2> /dev/null")
+      communicator.expect_command("/sbin/ifup eth0")
+      communicator.expect_command("/sbin/ifup eth1")
+      described_class.configure_networks(machine, [network_0, network_1])
+    end
+  end
+end