diff --git a/plugins/hosts/null/host.rb b/plugins/hosts/null/host.rb
new file mode 100644
index 000000000..b90b1503c
--- /dev/null
+++ b/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
diff --git a/plugins/hosts/null/plugin.rb b/plugins/hosts/null/plugin.rb
new file mode 100644
index 000000000..2c72912fb
--- /dev/null
+++ b/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
diff --git a/test/unit/base.rb b/test/unit/base.rb
index db530c2e4..c9ffe6654 100644
--- a/test/unit/base.rb
+++ b/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
diff --git a/test/unit/plugins/providers/virtualbox/action/prepare_nfs_settings_test.rb b/test/unit/plugins/providers/virtualbox/action/prepare_nfs_settings_test.rb
index c3f3e6016..4751c083e 100644
--- a/test/unit/plugins/providers/virtualbox/action/prepare_nfs_settings_test.rb
+++ b/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) {