diff --git a/plugins/provisioners/ansible/config.rb b/plugins/provisioners/ansible/config.rb
index f702cf827..79ddcce30 100644
--- a/plugins/provisioners/ansible/config.rb
+++ b/plugins/provisioners/ansible/config.rb
@@ -33,7 +33,7 @@ module VagrantPlugins
         @skip_tags         = UNSET_VALUE
         @start_at_task     = UNSET_VALUE
         @groups            = UNSET_VALUE
-        @host_key_checking = "false"
+        @host_key_checking = UNSET_VALUE
         @raw_arguments     = UNSET_VALUE
         @raw_ssh_args      = UNSET_VALUE
       end
@@ -42,16 +42,16 @@ module VagrantPlugins
         @playbook          = nil if @playbook == UNSET_VALUE
         @extra_vars        = nil if @extra_vars == UNSET_VALUE
         @inventory_path    = nil if @inventory_path == UNSET_VALUE
-        @ask_sudo_pass     = nil if @ask_sudo_pass == UNSET_VALUE
+        @ask_sudo_pass     = false unless @ask_sudo_pass == true
         @limit             = nil if @limit == UNSET_VALUE
-        @sudo              = nil if @sudo == UNSET_VALUE
+        @sudo              = false unless @sudo == true
         @sudo_user         = nil if @sudo_user == UNSET_VALUE
         @verbose           = nil if @verbose == UNSET_VALUE
         @tags              = nil if @tags == UNSET_VALUE
         @skip_tags         = nil if @skip_tags == UNSET_VALUE
         @start_at_task     = nil if @start_at_task == UNSET_VALUE
         @groups            = {}  if @groups == UNSET_VALUE
-        @host_key_checking = nil if @host_key_checking == UNSET_VALUE
+        @host_key_checking = false unless @host_key_checking == true
         @raw_arguments     = nil if @raw_arguments == UNSET_VALUE
         @raw_ssh_args      = nil if @raw_ssh_args == UNSET_VALUE
       end
diff --git a/test/unit/plugins/provisioners/ansible/config_test.rb b/test/unit/plugins/provisioners/ansible/config_test.rb
new file mode 100644
index 000000000..6e0ec3301
--- /dev/null
+++ b/test/unit/plugins/provisioners/ansible/config_test.rb
@@ -0,0 +1,179 @@
+require_relative "../../../base"
+require_relative "../support/shared/config"
+
+require Vagrant.source_root.join("plugins/provisioners/ansible/config")
+
+describe VagrantPlugins::Ansible::Config do
+  include_context "unit"
+
+  subject { described_class.new }
+
+  let(:machine) { double("machine", env: Vagrant::Environment.new) }
+  let(:existing_file) { File.expand_path(__FILE__) }
+  let(:non_existing_file) { "/this/does/not/exist" }
+
+  it "supports a list of options" do
+    config_options = subject.public_methods(false).find_all { |i| i.to_s.end_with?('=') }
+    config_options.map! { |i| i.to_s.sub('=', '') }
+    supported_options = %w( ask_sudo_pass
+                            extra_vars
+                            groups
+                            host_key_checking
+                            inventory_path
+                            limit
+                            playbook
+                            raw_arguments
+                            raw_ssh_args
+                            skip_tags
+                            start_at_task
+                            sudo
+                            sudo_user
+                            tags
+                            verbose )
+
+    expect(config_options.sort).to eql(supported_options)
+  end
+
+  it "assigns default values to unset options" do
+    subject.finalize!
+
+    expect(subject.playbook).to be_nil
+    expect(subject.extra_vars).to be_nil
+    expect(subject.ask_sudo_pass).to be_false
+    expect(subject.limit).to be_nil
+    expect(subject.sudo).to be_false
+    expect(subject.sudo_user).to be_nil
+    expect(subject.verbose).to be_nil
+    expect(subject.tags).to be_nil
+    expect(subject.skip_tags).to be_nil
+    expect(subject.start_at_task).to be_nil
+    expect(subject.groups).to eq({})
+    expect(subject.host_key_checking).to be_false
+    expect(subject.raw_arguments).to be_nil
+    expect(subject.raw_ssh_args).to be_nil
+  end
+
+  describe "host_key_checking option" do
+    it_behaves_like "any VagrantConfigProvisioner strict boolean attribute", :host_key_checking, false
+  end
+  describe "ask_sudo_pass option" do
+    it_behaves_like "any VagrantConfigProvisioner strict boolean attribute", :ask_sudo_pass, false
+  end
+  describe "sudo option" do
+    it_behaves_like "any VagrantConfigProvisioner strict boolean attribute", :sudo, false
+  end
+
+  describe "#validate" do
+    before do
+      subject.playbook = existing_file
+    end
+
+    it "passes if the playbook option refers to an existing file" do
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([])
+    end
+
+    it "returns an error if the playbook option is undefined" do
+      subject.playbook = nil
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([
+        I18n.t("vagrant.provisioners.ansible.no_playbook")
+      ])
+    end
+
+    it "returns an error if the playbook file does not exist" do
+      subject.playbook = non_existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([
+        I18n.t("vagrant.provisioners.ansible.playbook_path_invalid",
+               :path => non_existing_file)
+      ])
+    end
+
+    it "passes if the extra_vars option refers to an existing file" do
+      subject.extra_vars = existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([])
+    end
+
+    it "passes if the extra_vars option is a hash" do
+      subject.extra_vars = { var1: 1, var2: "foo" }
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([])
+    end
+
+    it "returns an error if the extra_vars option refers to a file that does not exist" do
+      subject.extra_vars = non_existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([
+        I18n.t("vagrant.provisioners.ansible.extra_vars_invalid",
+               :type  => subject.extra_vars.class.to_s,
+               :value => subject.extra_vars.to_s)
+      ])
+    end
+
+    it "returns an error if the extra_vars option is of wrong data type" do
+      subject.extra_vars = ["var1", 3, "var2", 5]
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([
+        I18n.t("vagrant.provisioners.ansible.extra_vars_invalid",
+               :type  => subject.extra_vars.class.to_s,
+               :value => subject.extra_vars.to_s)
+      ])
+    end
+
+    it "passes if inventory_path refers to an existing location" do
+      subject.inventory_path = existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([])
+    end
+
+    it "returns an error if inventory_path is specified, but does not exist" do
+      subject.inventory_path = non_existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to eql([
+        I18n.t("vagrant.provisioners.ansible.inventory_path_invalid",
+               :path => non_existing_file)
+      ])
+    end
+
+    it "it collects and returns all detected errors" do
+      subject.playbook = non_existing_file
+      subject.inventory_path = non_existing_file
+      subject.extra_vars = non_existing_file
+      subject.finalize!
+
+      result = subject.validate(machine)
+      expect(result["ansible provisioner"]).to include(
+        I18n.t("vagrant.provisioners.ansible.playbook_path_invalid",
+               :path => non_existing_file))
+      expect(result["ansible provisioner"]).to include(
+        I18n.t("vagrant.provisioners.ansible.extra_vars_invalid",
+               :type  => subject.extra_vars.class.to_s,
+               :value => subject.extra_vars.to_s))
+      expect(result["ansible provisioner"]).to include(
+        I18n.t("vagrant.provisioners.ansible.inventory_path_invalid",
+               :path => non_existing_file))
+    end
+
+  end
+
+end
diff --git a/test/unit/plugins/provisioners/ansible/provisioner_test.rb b/test/unit/plugins/provisioners/ansible/provisioner_test.rb
new file mode 100644
index 000000000..007d3b98a
--- /dev/null
+++ b/test/unit/plugins/provisioners/ansible/provisioner_test.rb
@@ -0,0 +1,448 @@
+require_relative "../../../base"
+
+require Vagrant.source_root.join("plugins/provisioners/ansible/config")
+require Vagrant.source_root.join("plugins/provisioners/ansible/provisioner")
+
+#
+# Helper Functions
+#
+
+def find_last_argument_after(ref_index, ansible_playbook_args, arg_pattern)
+  subset = ansible_playbook_args[(ref_index + 1)..(ansible_playbook_args.length-2)].reverse
+  subset.each do |i|
+    return true if i =~ arg_pattern
+  end
+  return false
+end
+
+describe VagrantPlugins::Ansible::Provisioner do
+  include_context "unit"
+
+  subject { described_class.new(machine, config) }
+
+  let(:iso_env) do
+    # We have to create a Vagrantfile so there is a Vagrant Environment to provide:
+    # - a location for the generated inventory
+    # - multi-machines configuration
+
+    env = isolated_environment
+    env.vagrantfile(<<-VF)
+Vagrant.configure("2") do |config|
+  config.vm.box = "base"
+  config.vm.define :machine1
+  config.vm.define :machine2
+end
+VF
+    env.create_vagrant_env
+  end
+
+  let(:machine) { iso_env.machine(iso_env.machine_names[0], :dummy) }
+  let(:config)  { VagrantPlugins::Ansible::Config.new }
+  let(:ssh_info) {{
+    private_key_path: ['/path/to/my/key'],
+    username: 'testuser',
+    host: '127.0.0.1',
+    port: 2223
+  }}
+
+  let(:existing_file) { File.expand_path(__FILE__) }
+  let(:generated_inventory_dir) { File.join(machine.env.local_data_path, %w(provisioners ansible inventory)) }
+  let(:generated_inventory_file) { File.join(generated_inventory_dir, 'vagrant_ansible_inventory') }
+
+  before do
+    machine.stub(ssh_info: ssh_info)
+    machine.env.stub(active_machines: [[iso_env.machine_names[0], :dummy], [iso_env.machine_names[1], :dummy]])
+
+    config.playbook = 'playbook.yml'
+  end
+
+  #
+  # Class methods for code reuse across examples
+  #
+
+  def self.it_should_set_arguments_and_environment_variables(expected_args_count = 5, expected_vars_count = 3, expected_host_key_checking = false)
+    it "sets implicit arguments in a specific order" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+
+        expect(args[0]).to eq("ansible-playbook")
+        expect(args[1]).to eq("--private-key=#{machine.ssh_info[:private_key_path][0]}")
+        expect(args[2]).to eq("--user=#{machine.ssh_info[:username]}")
+
+        limit_index = args.index("--limit=#{machine.name}")
+        expect(limit_index).to be > 2
+        expect(limit_index).to be < 5
+        if (limit_index == 4)
+          expect(args[3]).to match("--connection=ssh")
+        end
+
+        inventory_count = args.count { |x| x =~ /--inventory-file=.+/ }
+        expect(inventory_count).to be > 0
+
+        expect(args[args.length-2]).to eq("playbook.yml")
+      }
+    end
+
+    it "exports environment variables" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        cmd_opts = args.last
+        expect(cmd_opts[:env]['ANSIBLE_FORCE_COLOR']).to eql("true")
+        expect(cmd_opts[:env]['ANSIBLE_HOST_KEY_CHECKING']).to eql(expected_host_key_checking.to_s)
+        expect(cmd_opts[:env]['PYTHONUNBUFFERED']).to eql(1)
+      }
+    end
+
+    # "roughly" verify that only expected args/vars have been defined by the provisioner
+    it "sets the expected number of arguments and environment variables" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        expect(args.length-2).to eq(expected_args_count)
+        expect(args.last[:env].length).to eq(expected_vars_count)
+      }
+    end
+  end
+
+  def self.it_should_set_optional_arguments(arg_map)
+    it "sets optional arguments" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        arg_map.each_pair do |vagrant_option, ansible_argument|
+          index = args.index(ansible_argument)
+          if config.send(vagrant_option)
+            expect(index).to be > 0
+          else
+            expect(index).to be_nil
+          end
+        end
+      }
+    end
+  end
+
+  def self.it_should_use_smart_transport_mode
+    it "does not export ANSIBLE_SSH_ARGS" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        cmd_opts = args.last
+        expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to be_nil
+      }
+    end
+
+    it "does not force any transport mode" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        total = args.count { |x| x =~ /--connection=\w+/ }
+        expect(total).to eql(0)
+      }
+    end
+  end
+
+  def self.it_should_use_transport_mode(transport_mode)
+    it "it enables '#{transport_mode}' transport mode" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        index = args.rindex("--connection=#{transport_mode}")
+        expect(index).to be > 0
+        expect(find_last_argument_after(index, args, /--connection=\w+/)).to be_false
+      }
+    end
+  end
+
+  def self.it_should_force_ssh_transport_mode
+    it_should_use_transport_mode('ssh')
+
+    it "configures ControlPersist (like Ansible defaults) via ANSIBLE_SSH_ARGS" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        cmd_opts = args.last
+        expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to include("-o ControlMaster=auto")
+        expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to include("-o ControlPersist=60s")
+      }
+    end
+  end
+
+  def self.it_should_create_and_use_generated_inventory
+    it "generates an inventory with all active machines" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        expect(config.inventory_path).to be_nil
+        expect(File.exists?(generated_inventory_file)).to be_true
+        inventory_content = File.read(generated_inventory_file)
+        expect(inventory_content).to include("#{machine.name} ansible_ssh_host=#{machine.ssh_info[:host]} ansible_ssh_port=#{machine.ssh_info[:port]}\n")
+        expect(inventory_content).to include("# MISSING: '#{iso_env.machine_names[1]}' machine was probably removed without using Vagrant. This machine should be recreated.\n")
+      }
+    end
+
+    it "sets as ansible inventory the directory containing the auto-generated inventory file" do
+      expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+        inventory_index = args.rindex("--inventory-file=#{generated_inventory_dir}")
+        expect(inventory_index).to be > 0
+        expect(find_last_argument_after(inventory_index, args, /--inventory-file=\w+/)).to be_false
+      }
+    end
+  end
+
+  describe "#provision" do
+
+    before do
+      unless example.metadata[:skip_before]
+        config.finalize!
+        Vagrant::Util::Subprocess.stub(execute: Vagrant::Util::Subprocess::Result.new(0, "", ""))
+      end
+    end
+
+    after do
+      unless example.metadata[:skip_after]
+        subject.provision
+      end
+    end
+
+    describe 'when ansible-playbook fails' do
+      it "raises an error", skip_before: true, skip_after: true do
+        config.finalize!
+        Vagrant::Util::Subprocess.stub(execute: Vagrant::Util::Subprocess::Result.new(1, "", ""))
+
+        expect {subject.provision}.to raise_error(Vagrant::Errors::AnsibleFailed)
+      end
+    end
+
+    describe "with default options" do
+      it_should_set_arguments_and_environment_variables
+      it_should_use_smart_transport_mode
+      it_should_create_and_use_generated_inventory
+
+      it "does not add any group section to the generated inventory" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          inventory_content = File.read(generated_inventory_file)
+          expect(inventory_content).to_not match(/^\s*\[^\\+\]\s*$/)
+
+          # Note:
+          # The expectation below is a workaround to a possible misuse (or bug) in RSpec/Ruby stack.
+          # If 'args' variable is not required by in this block, the "Vagrant::Util::Subprocess).to receive"
+          # surprisingly expects to receive "no args".
+          # This problem can be "solved" by using args the "unnecessary" (but harmless) expectation below:
+          expect(args.length).to be > 0
+        }
+      end
+    end
+
+    describe "with groups option" do
+      it_should_create_and_use_generated_inventory
+
+      it "adds group sections to the generated inventory" do
+        config.groups = {
+          "group1" => "#{machine.name}",
+          "group1:children" => 'bar',
+          "group2" => ["iso_env.machine_names[1]"],
+          "group3" => ["unknown", "#{machine.name}"],
+          "bar" => ["#{machine.name}", "group3"],
+          "bar:children" => ["group1", "group2", "group3", "group4"],
+          "bar:vars" => ["myvar=foo"],
+        }
+
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          inventory_content = File.read(generated_inventory_file)
+
+          # Group variables are intentionally not supported in generated inventory
+          expect(inventory_content).not_to match(/^\[.*:vars\]$/)
+
+          # Accept String instead of Array for group that contains a single item
+          expect(inventory_content).to include("[group1]\n#{machine.name}\n")
+          expect(inventory_content).to include("[group1:children]\nbar\n")
+
+          # Skip "lost" machines
+          expect(inventory_content).to include("[group2]\n\n")
+
+          # Skip "unknown" machines
+          expect(inventory_content).to include("[group3]\n#{machine.name}\n")
+
+          # Don't mix group names and host names
+          expect(inventory_content).to include("[bar]\n#{machine.name}\n")
+
+          # A group of groups only includes declared groups
+          expect(inventory_content).not_to match(/^group4$/)
+          expect(inventory_content).to include("[bar:children]\ngroup1\ngroup2\ngroup3\n")
+        }
+      end
+    end
+
+    describe "with host_key_checking option enabled" do
+      before do
+        config.host_key_checking = true
+      end
+
+      it_should_set_arguments_and_environment_variables 5, 3, true
+      it_should_use_smart_transport_mode
+    end
+
+    describe "with boolean (flag) options disabled" do
+      before do
+        config.sudo = false
+        config.ask_sudo_pass = false
+
+        config.sudo_user = 'root'
+      end
+
+      it_should_set_arguments_and_environment_variables 6
+      it_should_set_optional_arguments({ "sudo_user" => "--sudo-user=root" })
+
+      it "it does not set boolean flag when corresponding option is set to false" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          expect(args.index("--sudo")).to be_nil
+          expect(args.index("--ask-sudo-pass")).to be_nil
+        }
+      end
+    end
+
+    describe "with raw_arguments option" do
+      before do
+        config.sudo = false
+        config.skip_tags = %w(foo bar)
+        config.raw_arguments = ["--connection=paramiko",
+                                "--skip-tags=ignored",
+                                "--module-path=/other/modules",
+                                "--sudo",
+                                "--inventory-file=/forget/it/my/friend",
+                                "--new-arg=yeah"]
+      end
+
+      it_should_set_arguments_and_environment_variables 12
+      it_should_create_and_use_generated_inventory
+      it_should_use_transport_mode('paramiko')
+
+      it "sets all raw arguments" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          config.raw_arguments.each do |raw_arg|
+            expect(args).to include(raw_arg)
+          end
+        }
+      end
+
+      it "sets raw arguments before arguments related to supported options" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          expect(args.index("--skip-tags=foo,bar")).to be > args.index("--skip-tags=ignored")
+        }
+      end
+
+      it "sets boolean flag (e.g. --sudo) defined in raw_arguments, even if corresponding option is set to false" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          expect(args).to include('--sudo')
+        }
+      end
+
+    end
+
+    describe "with limit option" do
+      before do
+        config.limit = %w(foo !bar)
+      end
+
+      it_should_set_arguments_and_environment_variables 6
+      it_should_set_optional_arguments({ "limit" => "--limit=foo,!bar" })
+
+      it "sets custom limit argument after implicit default limit" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          expect(args.index("--limit=foo,!bar")).to be > args.index("--limit=#{machine.name}")
+        }
+      end
+    end
+
+    describe "with inventory_path option" do
+      before do
+        config.inventory_path = existing_file
+      end
+
+      it_should_set_arguments_and_environment_variables
+      it_should_use_smart_transport_mode
+
+      it "does not generate the inventory and uses given inventory path instead" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          expect(args).to include("--inventory-file=#{existing_file}")
+          expect(args).not_to include("--inventory-file=#{generated_inventory_file}")
+          expect(File.exists?(generated_inventory_file)).to be_false
+        }
+      end
+    end
+
+    describe "with raw_ssh_args" do
+      before do
+        config.raw_ssh_args = ['-o ControlMaster=no']
+      end
+
+      it_should_set_arguments_and_environment_variables 6, 4
+      it_should_force_ssh_transport_mode
+
+      it "passes custom SSH options via ANSIBLE_SSH_ARGS with the highest priority" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          cmd_opts = args.last
+          raw_opt_index = cmd_opts[:env]['ANSIBLE_SSH_ARGS'].index("-o ControlMaster=no")
+          default_opt_index = cmd_opts[:env]['ANSIBLE_SSH_ARGS'].index("-o ControlMaster=auto")
+          expect(raw_opt_index).not_to be_nil
+          expect(default_opt_index).not_to be_nil
+          expect(raw_opt_index).to be < default_opt_index
+        }
+      end
+
+    end
+
+    describe "with multiple SSH identities" do
+      before do
+        ssh_info[:private_key_path] = ['/path/to/my/key', '/an/other/identity', '/yet/an/other/key']
+      end
+
+      it_should_set_arguments_and_environment_variables 6, 4
+      it_should_force_ssh_transport_mode
+
+      it "passes additional Identity Files via ANSIBLE_SSH_ARGS" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          cmd_opts = args.last
+          expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to include("-o IdentityFile=/an/other/identity")
+          expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to include("-o IdentityFile=/yet/an/other/key")
+        }
+      end
+    end
+
+    describe "with ssh forwarding enabled" do
+      before do
+        ssh_info[:forward_agent] = true
+      end
+
+      it_should_set_arguments_and_environment_variables 6, 4
+      it_should_force_ssh_transport_mode
+
+      it "enables SSH-Forwarding via ANSIBLE_SSH_ARGS" do
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          cmd_opts = args.last
+          expect(cmd_opts[:env]['ANSIBLE_SSH_ARGS']).to include("-o ForwardAgent=yes")
+        }
+      end
+    end
+
+    # Note:
+    # The Vagrant Ansible provisioner does not validate the coherency of arguments combination,
+    # and let ansible-playbook complaign.
+    describe "with a maximum of options" do
+      before do
+        # command line arguments
+        config.extra_vars = "@#{existing_file}"
+        config.sudo = true
+        config.sudo_user = 'deployer'
+        config.verbose = "vvv"
+        config.ask_sudo_pass = true
+        config.tags = %w(db www)
+        config.skip_tags = %w(foo bar)
+        config.limit = 'machine*:&vagrant:!that_one'
+        config.start_at_task = 'an awesome task'
+
+        # environment variables
+        config.host_key_checking = true
+        config.raw_ssh_args = ['-o ControlMaster=no']
+      end
+
+      it_should_set_arguments_and_environment_variables 15, 4, true
+      it_should_force_ssh_transport_mode
+      it_should_set_optional_arguments({  "extra_vars"    => "--extra-vars=@#{File.expand_path(__FILE__)}",
+                                          "sudo"          => "--sudo",
+                                          "sudo_user"     => "--sudo-user=deployer",
+                                          "verbose"       => "-vvv",
+                                          "ask_sudo_pass" => "--ask-sudo-pass",
+                                          "tags"          => "--tags=db,www",
+                                          "skip_tags"     => "--skip-tags=foo,bar",
+                                          "limit"         => "--limit=machine*:&vagrant:!that_one",
+                                          "start_at_task" => '--start-at-task=an awesome task',
+                                        })
+    end
+
+  end
+end
diff --git a/test/unit/plugins/provisioners/support/shared/config.rb b/test/unit/plugins/provisioners/support/shared/config.rb
new file mode 100644
index 000000000..052a10b4a
--- /dev/null
+++ b/test/unit/plugins/provisioners/support/shared/config.rb
@@ -0,0 +1,28 @@
+shared_examples_for 'any VagrantConfigProvisioner strict boolean attribute' do |attr_name, attr_default_value|
+
+  [true, false].each do |bool|
+    it "returns the assigned boolean value (#{bool})" do
+      subject.send("#{attr_name}=", bool)
+      subject.finalize!
+
+      expect(subject.send(attr_name)).to eql(bool)
+    end
+  end
+
+  it "returns the default value (#{attr_default_value}) if undefined" do
+    subject.finalize!
+
+    expect(subject.send(attr_name)).to eql(attr_default_value)
+  end
+
+  [nil, 'true', 'false', 1, 0, 'this is not a boolean'].each do |nobool|
+    it "returns the default value when assigned value is invalid (#{nobool.class}: #{nobool})" do
+      subject.send("#{attr_name}=", nobool)
+      subject.finalize!
+
+      expect(subject.send(attr_name)).to eql(attr_default_value)
+    end
+  end
+
+end
+