diff --git a/lib/vagrant/plugin/v2/config.rb b/lib/vagrant/plugin/v2/config.rb
index 533e00bce..a74eb670c 100644
--- a/lib/vagrant/plugin/v2/config.rb
+++ b/lib/vagrant/plugin/v2/config.rb
@@ -5,6 +5,13 @@ module Vagrant
       # V2. Any configuration key plugins for V2 should inherit from this
       # class.
       class Config
+        # This constant represents an unset value. This is useful so it is
+        # possible to know the difference between a configuration value that
+        # was never set, and a value that is nil (explicitly). Best practice
+        # is to initialize all variables to this value, then the {#merge}
+        # method below will "just work" in many cases.
+        UNSET_VALUE = Object.new
+
         # This is called as a last-minute hook that allows the configuration
         # object to finalize itself before it will be put into use. This is
         # a useful place to do some defaults in the case the user didn't
@@ -43,7 +50,9 @@ module Vagrant
               # configuration classes to still hold around internal state
               # that isn't propagated.
               if !key.to_s.start_with?("@__")
-                result.instance_variable_set(key, obj.instance_variable_get(key))
+                # Don't set the value if it is the unset value, either.
+                value = obj.instance_variable_get(key)
+                result.instance_variable_set(key, value) if value != UNSET_VALUE
               end
             end
           end
diff --git a/test/unit/vagrant/plugin/v2/command_test.rb b/test/unit/vagrant/plugin/v2/command_test.rb
new file mode 100644
index 000000000..ce3faf139
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/command_test.rb
@@ -0,0 +1,142 @@
+require File.expand_path("../../../../base", __FILE__)
+require 'optparse'
+
+describe Vagrant::Plugin::V2::Command do
+  describe "parsing options" do
+    let(:klass) do
+      Class.new(described_class) do
+        # Make the method public since it is normally protected
+        public :parse_options
+      end
+    end
+
+    it "returns the remaining arguments" do
+      options = {}
+      opts = OptionParser.new do |o|
+        o.on("-f") do |f|
+          options[:f] = f
+        end
+      end
+
+      result = klass.new(["-f", "foo"], nil).parse_options(opts)
+
+      # Check the results
+      options[:f].should be
+      result.should == ["foo"]
+    end
+
+    it "creates an option parser if none is given" do
+      result = klass.new(["foo"], nil).parse_options(nil)
+      result.should == ["foo"]
+    end
+
+    ["-h", "--help"].each do |help_string|
+      it "returns nil and prints the help if '#{help_string}' is given" do
+        instance = klass.new([help_string], nil)
+        instance.should_receive(:safe_puts)
+        instance.parse_options(OptionParser.new).should be_nil
+      end
+    end
+
+    it "raises an error if invalid options are given" do
+      instance = klass.new(["-f"], nil)
+      expect { instance.parse_options(OptionParser.new) }.
+        to raise_error(Vagrant::Errors::CLIInvalidOptions)
+    end
+  end
+
+  describe "target VMs" do
+    let(:klass) do
+      Class.new(described_class) do
+        # Make the method public since it is normally protected
+        public :with_target_vms
+      end
+    end
+
+    let(:environment) do
+      env = double("environment")
+      env.stub(:root_path => "foo")
+      env
+    end
+
+    let(:instance)    { klass.new([], environment) }
+
+    it "should raise an exception if a root_path is not available" do
+      environment.stub(:root_path => nil)
+
+      expect { instance.with_target_vms }.
+        to raise_error(Vagrant::Errors::NoEnvironmentError)
+    end
+
+    it "should yield every VM in order is no name is given" do
+      foo_vm = double("foo")
+      foo_vm.stub(:name).and_return("foo")
+
+      bar_vm = double("bar")
+      bar_vm.stub(:name).and_return("bar")
+
+      environment.stub(:machine_names => [:foo, :bar])
+      environment.stub(:machine).with(:foo, :virtualbox).and_return(foo_vm)
+      environment.stub(:machine).with(:bar, :virtualbox).and_return(bar_vm)
+
+      vms = []
+      instance.with_target_vms do |vm|
+        vms << vm
+      end
+
+      vms.should == [foo_vm, bar_vm]
+    end
+
+    it "raises an exception if the named VM doesn't exist" do
+      environment.stub(:machine_names => [:default])
+      environment.stub(:machine).with(:foo, anything).and_return(nil)
+
+      expect { instance.with_target_vms("foo") }.
+        to raise_error(Vagrant::Errors::VMNotFoundError)
+    end
+
+    it "yields the given VM if a name is given" do
+      foo_vm = double("foo")
+
+      environment.stub(:machine).with(:foo, :virtualbox).and_return(foo_vm)
+
+      vms = []
+      instance.with_target_vms("foo") { |vm| vms << vm }
+      vms.should == [foo_vm]
+    end
+  end
+
+  describe "splitting the main and subcommand args" do
+    let(:instance) do
+      Class.new(described_class) do
+        # Make the method public since it is normally protected
+        public :split_main_and_subcommand
+      end.new(nil, nil)
+    end
+
+    it "should work when given all 3 parts" do
+      result = instance.split_main_and_subcommand(["-v", "status", "-h", "-v"])
+      result.should == [["-v"], "status", ["-h", "-v"]]
+    end
+
+    it "should work when given only a subcommand and args" do
+      result = instance.split_main_and_subcommand(["status", "-h"])
+      result.should == [[], "status", ["-h"]]
+    end
+
+    it "should work when given only main flags" do
+      result = instance.split_main_and_subcommand(["-v", "-h"])
+      result.should == [["-v", "-h"], nil, []]
+    end
+
+    it "should work when given only a subcommand" do
+      result = instance.split_main_and_subcommand(["status"])
+      result.should == [[], "status", []]
+    end
+
+    it "works when there are other non-flag args after the subcommand" do
+      result = instance.split_main_and_subcommand(["-v", "box", "add", "-h"])
+      result.should == [["-v"], "box", ["add", "-h"]]
+    end
+  end
+end
diff --git a/test/unit/vagrant/plugin/v2/communicator_test.rb b/test/unit/vagrant/plugin/v2/communicator_test.rb
new file mode 100644
index 000000000..7abf2abc1
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/communicator_test.rb
@@ -0,0 +1,9 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Communicator do
+  let(:machine)  { Object.new }
+
+  it "should not match by default" do
+    described_class.match?(machine).should_not be
+  end
+end
diff --git a/test/unit/vagrant/plugin/v2/config_test.rb b/test/unit/vagrant/plugin/v2/config_test.rb
new file mode 100644
index 000000000..6e32c814c
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/config_test.rb
@@ -0,0 +1,60 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Config do
+  include_context "unit"
+
+  let(:foo_class) do
+    Class.new(described_class) do
+      attr_accessor :one
+      attr_accessor :two
+    end
+  end
+
+  let(:unset_value) { described_class.const_get("UNSET_VALUE") }
+
+  describe "merging" do
+    it "should merge by default by simply copying each instance variable" do
+      one = foo_class.new
+      one.one = 2
+      one.two = 1
+
+      two = foo_class.new
+      two.two = 5
+
+      result = one.merge(two)
+      result.one.should == 2
+      result.two.should == 5
+    end
+
+    it "prefers any set value over an UNSET_VALUE" do
+      one = foo_class.new
+      one.one = 1
+      one.two = 2
+
+      two = foo_class.new
+      two.one = unset_value
+      two.two = 5
+
+      result = one.merge(two)
+      result.one.should == 1
+      result.two.should == 5
+    end
+
+    it "doesn't merge values that start with a double underscore" do
+      one = foo_class.new
+      one.one = 1
+      one.two = 1
+      one.instance_variable_set(:@__bar, "one")
+
+      two = foo_class.new
+      two.two = 2
+      two.instance_variable_set(:@__bar, "two")
+
+      # Merge and verify
+      result = one.merge(two)
+      result.one.should == 1
+      result.two.should == 2
+      result.instance_variable_get(:@__bar).should be_nil
+    end
+  end
+end
diff --git a/test/unit/vagrant/plugin/v2/host_test.rb b/test/unit/vagrant/plugin/v2/host_test.rb
new file mode 100644
index 000000000..b1822c19b
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/host_test.rb
@@ -0,0 +1,5 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Host do
+  # No tests.
+end
diff --git a/test/unit/vagrant/plugin/v2/manager_test.rb b/test/unit/vagrant/plugin/v2/manager_test.rb
new file mode 100644
index 000000000..0929bc5f0
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/manager_test.rb
@@ -0,0 +1,114 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Manager do
+  include_context "unit"
+
+  let(:instance) { described_class.new }
+
+  def plugin
+    p = Class.new(Vagrant.plugin("2"))
+    yield p
+    p
+  end
+
+  it "should enumerate registered communicator classes" do
+    pA = plugin do |p|
+      p.communicator("foo") { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.communicator("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.communicators.length.should == 2
+    instance.communicators[:foo].should == "bar"
+    instance.communicators[:bar].should == "baz"
+  end
+
+  it "should enumerate registered configuration classes" do
+    pA = plugin do |p|
+      p.config("foo") { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.config("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.config.length.should == 2
+    instance.config[:foo].should == "bar"
+    instance.config[:bar].should == "baz"
+  end
+
+  it "should enumerate registered upgrade safe config classes" do
+    pA = plugin do |p|
+      p.config("foo", true) { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.config("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.config_upgrade_safe.length.should == 1
+    instance.config_upgrade_safe[:foo].should == "bar"
+  end
+
+  it "should enumerate registered guest classes" do
+    pA = plugin do |p|
+      p.guest("foo") { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.guest("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.guests.length.should == 2
+    instance.guests[:foo].should == "bar"
+    instance.guests[:bar].should == "baz"
+  end
+
+  it "should enumerate registered host classes" do
+    pA = plugin do |p|
+      p.host("foo") { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.host("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.hosts.length.should == 2
+    instance.hosts[:foo].should == "bar"
+    instance.hosts[:bar].should == "baz"
+  end
+
+  it "should enumerate registered provider classes" do
+    pA = plugin do |p|
+      p.provider("foo") { "bar" }
+    end
+
+    pB = plugin do |p|
+      p.provider("bar") { "baz" }
+    end
+
+    instance.register(pA)
+    instance.register(pB)
+
+    instance.providers.length.should == 2
+    instance.providers[:foo].should == "bar"
+    instance.providers[:bar].should == "baz"
+  end
+end
diff --git a/test/unit/vagrant/plugin/v2/plugin_test.rb b/test/unit/vagrant/plugin/v2/plugin_test.rb
new file mode 100644
index 000000000..c12cc32b0
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/plugin_test.rb
@@ -0,0 +1,278 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Plugin do
+  after(:each) do
+    # We want to make sure that the registered plugins remains empty
+    # after each test.
+    described_class.manager.reset!
+  end
+
+  it "should be able to set and get the name" do
+    plugin = Class.new(described_class) do
+      name "foo"
+    end
+
+    plugin.name.should == "foo"
+  end
+
+  it "should be able to set and get the description" do
+    plugin = Class.new(described_class) do
+      description "bar"
+    end
+
+    plugin.description.should == "bar"
+  end
+
+  describe "action hooks" do
+    it "should register action hooks" do
+      plugin = Class.new(described_class) do
+        action_hook("foo") { "bar" }
+      end
+
+      hooks = plugin.action_hook("foo")
+      hooks.length.should == 1
+      hooks[0].call.should == "bar"
+    end
+  end
+
+  describe "commands" do
+    it "should register command classes" do
+      plugin = Class.new(described_class) do
+        command("foo") { "bar" }
+      end
+
+      plugin.command[:foo].should == "bar"
+    end
+
+    ["spaces bad", "sym^bols"].each do |bad|
+      it "should not allow bad command name: #{bad}" do
+        plugin = Class.new(described_class)
+
+        expect { plugin.command(bad) {} }.
+          to raise_error(Vagrant::Plugin::V2::InvalidCommandName)
+      end
+    end
+
+    it "should lazily register command classes" do
+      # Below would raise an error if the value of the command class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+        command("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the command key that
+      # a proper error is raised.
+      expect {
+        plugin.command[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "communicators" do
+    it "should register communicator classes" do
+      plugin = Class.new(described_class) do
+        communicator("foo") { "bar" }
+      end
+
+      plugin.communicator[:foo].should == "bar"
+    end
+
+    it "should lazily register communicator classes" do
+      # Below would raise an error if the value of the class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+        communicator("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the configuration key that
+      # a proper error is raised.
+      expect {
+        plugin.communicator[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "configuration" do
+    it "should register configuration classes" do
+      plugin = Class.new(described_class) do
+        config("foo") { "bar" }
+      end
+
+      plugin.config[:foo].should == "bar"
+    end
+
+    it "should lazily register configuration classes" do
+      # Below would raise an error if the value of the config class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+        config("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the configuration key that
+      # a proper error is raised.
+      expect {
+        plugin.config[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "easy commands" do
+    it "should register with the commands" do
+      plugin = Class.new(described_class) do
+        easy_command("foo") {}
+      end
+
+      # Check that the command class subclasses the easy command base
+      plugin.command[:foo].should < Vagrant::Easy::CommandBase
+    end
+  end
+
+  describe "guests" do
+    it "should register guest classes" do
+      plugin = Class.new(described_class) do
+        guest("foo") { "bar" }
+      end
+
+      plugin.guest[:foo].should == "bar"
+    end
+
+    it "should lazily register guest classes" do
+      # Below would raise an error if the value of the guest class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+          guest("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the guest key that
+      # a proper error is raised.
+      expect {
+        plugin.guest[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "hosts" do
+    it "should register host classes" do
+      plugin = Class.new(described_class) do
+        host("foo") { "bar" }
+      end
+
+      plugin.host[:foo].should == "bar"
+    end
+
+    it "should lazily register host classes" do
+      # Below would raise an error if the value of the host class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+          host("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the host key that
+      # a proper error is raised.
+      expect {
+        plugin.host[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "providers" do
+    it "should register provider classes" do
+      plugin = Class.new(described_class) do
+        provider("foo") { "bar" }
+      end
+
+      plugin.provider[:foo].should == "bar"
+    end
+
+    it "should lazily register provider classes" do
+      # Below would raise an error if the value of the config class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+          provider("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the configuration key that
+      # a proper error is raised.
+      expect {
+        plugin.provider[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "provisioners" do
+    it "should register provisioner classes" do
+      plugin = Class.new(described_class) do
+        provisioner("foo") { "bar" }
+      end
+
+      plugin.provisioner[:foo].should == "bar"
+    end
+
+    it "should lazily register provisioner classes" do
+      # Below would raise an error if the value of the config class was
+      # evaluated immediately. By asserting that this does not raise an
+      # error, we verify that the value is actually lazily loaded
+      plugin = nil
+      expect {
+        plugin = Class.new(described_class) do
+          provisioner("foo") { raise StandardError, "FAIL!" }
+        end
+      }.to_not raise_error
+
+      # Now verify when we actually get the configuration key that
+      # a proper error is raised.
+      expect {
+        plugin.provisioner[:foo]
+      }.to raise_error(StandardError)
+    end
+  end
+
+  describe "plugin registration" do
+    let(:manager) { described_class.manager }
+
+    it "should have no registered plugins" do
+      manager.registered.should be_empty
+    end
+
+    it "should register a plugin when a name is set" do
+      plugin = Class.new(described_class) do
+        name "foo"
+      end
+
+      manager.registered.should == [plugin]
+    end
+
+    it "should register a plugin only once" do
+      plugin = Class.new(described_class) do
+        name "foo"
+        name "bar"
+      end
+
+      manager.registered.should == [plugin]
+    end
+  end
+end
diff --git a/test/unit/vagrant/plugin/v2/provider_test.rb b/test/unit/vagrant/plugin/v2/provider_test.rb
new file mode 100644
index 000000000..7a7b11876
--- /dev/null
+++ b/test/unit/vagrant/plugin/v2/provider_test.rb
@@ -0,0 +1,18 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V2::Provider do
+  let(:machine)  { Object.new }
+  let(:instance) { described_class.new(machine) }
+
+  it "should return nil by default for actions" do
+    instance.action(:whatever).should be_nil
+  end
+
+  it "should return nil by default for ssh info" do
+    instance.ssh_info.should be_nil
+  end
+
+  it "should return nil by default for state" do
+    instance.state.should be_nil
+  end
+end