kernel/v2: hostnames can be one character [GH-3713]

CHANGELOG.md

@@ -7,6 +7,10 @@ IMPROVEMENTS:
   - providers/docker: `build_args` config to specify extra args for
       `docker build`. [GH-3684]
 
+BUG FIXES:
+
+  - core: Hostnames can be one character. [GH-3713]
+
 ## 1.6.1 (May 7, 2014)
 
 IMPROVEMENTS:

plugins/kernel_v2/config/vm.rb

@@ -480,7 +480,7 @@ module VagrantPlugins
         end
 
         errors << I18n.t("vagrant.config.vm.hostname_invalid_characters") if \
-          @hostname && @hostname !~ /^[a-z0-9][-.a-z0-9]+$/i
+          @hostname && @hostname !~ /^[a-z0-9][-.a-z0-9]*$/i
 
         if @box_version
           @box_version.split(",").each do |v|

test/unit/plugins/kernel_v2/config/vm_test.rb

@@ -134,6 +134,16 @@ describe VagrantPlugins::Kernel_V2::VMConfig do
     end
   end
 
+  describe "#hostname" do
+    ["a", "foo", "foo-bar", "baz0"].each do |valid|
+      it "is valid: #{valid}" do
+        subject.hostname = valid
+        subject.finalize!
+        assert_valid
+      end
+    end
+  end
+
   describe "#network(s)" do
     it "defaults to forwarding SSH" do
       subject.finalize!