Allow automatic mac address assignment with virtuabox provider

plugins/providers/virtualbox/action/match_mac_address.rb

@@ -10,11 +10,14 @@ module VagrantPlugins
           # If we cloned, we don't need a base mac, it is already set!
           return @app.call(env) if env[:machine].config.vm.clone
 
-          raise Vagrant::Errors::VMBaseMacNotSpecified if !env[:machine].config.vm.base_mac
-
+          if env[:machine].config.vm.base_mac
             # Create the proc which we want to use to modify the virtual machine
             env[:ui].info I18n.t("vagrant.actions.vm.match_mac.matching")
             env[:machine].provider.driver.set_mac_address(env[:machine].config.vm.base_mac)
+          else
+            env[:ui].info I18n.t("vagrant.actions.vm.match_mac.generating")
+            env[:machine].provider.driver.set_mac_address(nil)
+          end
 
           @app.call(env)
         end

plugins/providers/virtualbox/driver/version_5_0.rb

@@ -635,6 +635,7 @@ module VagrantPlugins
         end
 
         def set_mac_address(mac)
+          mac = "auto" if !mac
           execute("modifyvm", @uuid, "--macaddress1", mac, retryable: true)
         end
 

templates/locales/en.yml

@@ -2177,6 +2177,7 @@ en:
             manually for more verbose error output.
         match_mac:
           matching: Matching MAC address for NAT networking...
+          generating: Generating MAC address for NAT networking...
           no_base_mac: |-
             No base MAC address was specified. This is required for the NAT networking
             to work properly (and hence port forwarding, SSH, etc.). Specifying this

test/unit/plugins/providers/virtualbox/action/match_mac_address_test.rb

@@ -0,0 +1,44 @@
+require_relative "../base"
+
+describe VagrantPlugins::ProviderVirtualBox::Action::MatchMACAddress do
+  let(:ui) { double("ui") }
+  let(:machine) { double("machine", config: config, provider: double("provider", driver: driver)) }
+  let(:driver) { double("driver") }
+  let(:env) {
+    {machine: machine, ui: ui}
+  }
+  let(:app) { double("app") }
+  let(:config) { double("config", vm: vm) }
+  let(:vm) { double("vm", clone: clone, base_mac: base_mac) }
+  let(:clone) { false }
+  let(:base_mac) { "00:00:00:00:00:00" }
+
+  let(:subject) { described_class.new(app, env) }
+
+  before do
+    allow(ui).to receive(:info)
+    allow(app).to receive(:call)
+  end
+
+  after { subject.call(env) }
+
+  it "should set the mac address" do
+    expect(driver).to receive(:set_mac_address).with(base_mac)
+  end
+
+  context "when clone is true" do
+    let(:clone) { true }
+
+    it "should not set mac address" do
+      expect(driver).not_to receive(:set_mac_address)
+    end
+  end
+
+  context "when base_mac is falsey" do
+    let(:base_mac) { nil }
+
+    it "should set mac address" do
+      expect(driver).to receive(:set_mac_address).with(base_mac)
+    end
+  end
+end

test/unit/plugins/providers/virtualbox/driver/version_5_0_test.rb

@@ -40,4 +40,24 @@ describe VagrantPlugins::ProviderVirtualBox::Driver::Version_5_0 do
 
     end
   end
+
+  describe "#set_mac_address" do
+    let(:mac) { "00:00:00:00:00:00" }
+
+    after { subject.set_mac_address(mac) }
+
+    it "should modify vm and set mac address" do
+      expect(subprocess).to receive(:execute).with("VBoxManage", "modifyvm", anything, "--macaddress1", mac, anything).
+        and_return(subprocess_result(exit_code: 0))
+    end
+
+    context "when mac address is falsey" do
+      let(:mac) { nil }
+
+      it "should modify vm and set mac address to automatic value" do
+        expect(subprocess).to receive(:execute).with("VBoxManage", "modifyvm", anything, "--macaddress1", "auto", anything).
+          and_return(subprocess_result(exit_code: 0))
+      end
+    end
+  end
 end