Get tests to pass

plugins/hosts/null/host.rb

@@ -0,0 +1,12 @@
+require "vagrant"
+
+module VagrantPlugins
+  module HostNull
+    class Host < Vagrant.plugin("2", :host)
+      def detect?
+        # This host can only be explicitly chosen.
+        false
+      end
+    end
+  end
+end

plugins/hosts/null/plugin.rb

@@ -0,0 +1,15 @@
+require "vagrant"
+
+module VagrantPlugins
+  module HostNull
+    class Plugin < Vagrant.plugin("2")
+      name "null host"
+      description "A host that implements no capabilities."
+
+      host("null") do
+        require_relative "host"
+        Host
+      end
+    end
+  end
+end

test/unit/base.rb

@@ -29,3 +29,11 @@ end
 # Configure VAGRANT_CWD so that the tests never find an actual
 # Vagrantfile anywhere, or at least this minimizes those chances.
 ENV["VAGRANT_CWD"] = Tempdir.new.path
+
+# Unset all host plugins so that we aren't executing subprocess things
+# to detect a host for every test.
+Vagrant.plugin("2").manager.registered.dup.each do |plugin|
+  if plugin.components.hosts.to_hash.length > 0
+    Vagrant.plugin("2").manager.unregister(plugin)
+  end
+end

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

@@ -1,6 +1,7 @@
 require_relative "../base"
 
 describe VagrantPlugins::ProviderVirtualBox::Action::PrepareNFSSettings do
+  include_context "unit"
   include_context "virtualbox"
 
   let(:machine) {