Vagrantfiles with only one `config.vm.define` are now considered multi-VM.

lib/vagrant/environment.rb

@@ -158,7 +158,7 @@ module Vagrant
       if parent
         parent.multivm?
       else
-        vms.length > 1
+        vms.length > 1 || vms.keys.first != DEFAULT_VM
       end
     end
 

test/vagrant/command/helpers_test.rb

@@ -39,11 +39,11 @@ class CommandHelpersTest < Test::Unit::TestCase
 
     context "without multivm" do
       setup do
-        @env.stubs(:vms).returns({ :one => 1 })
+        @env.stubs(:vms).returns({ :one => 1, :two => 2 })
       end
 
       should "raise an exception if a name is specified" do
-        instance = command(["foo"], @env)
+        instance = command(["foo"], vagrant_env)
         assert_raises(Vagrant::Errors::MultiVMEnvironmentRequired) {
           instance.target_vms
         }

test/vagrant/environment_test.rb

@@ -129,12 +129,16 @@ class EnvironmentTest < Test::Unit::TestCase
       assert env.multivm?
     end
 
-    should "return false if VM length is 1" do
+    should "return true if VM length is 1 and a sub-VM is defined" do
       env = vagrant_env(vagrantfile(<<-vf))
         config.vm.define :web
       vf
 
-      assert !env.multivm?
+      assert env.multivm?
+    end
+
+    should "return false if only default VM exists" do
+      assert !vagrant_env.multivm?
     end
   end