allow for custom min_username_length

change constant in user to be global range and not default

spec/models/user_spec.rb

@@ -174,7 +174,35 @@ describe User do
         myself.reload.username.should == 'HanSolo'
       end
     end
-
+    
+    describe 'allow custom minimum username length from site settings' do
+      before do
+        @custom_min = User::GLOBAL_USERNAME_LENGTH_RANGE.begin - 1
+        SiteSetting.stubs("min_username_length").returns(@custom_min)
+      end
+      
+      it 'should allow a shorter username than default' do
+        result = user.change_username('a' * @custom_min)
+        result.should_not be_false
+      end
+      
+      it 'should not allow a shorter username than limit' do
+        result = user.change_username('a' * (@custom_min - 1))
+        result.should be_false
+      end   
+      
+      it 'should not allow a longer username than limit' do
+        result = user.change_username('a' * (User::GLOBAL_USERNAME_LENGTH_RANGE.end + 1))
+        result.should be_false        
+      end
+      
+      it 'should use default length for validation if enforce_global_nicknames is true' do
+        SiteSetting.stubs('enforce_global_nicknames').returns(true)
+        
+        User::username_length.begin.should == User::GLOBAL_USERNAME_LENGTH_RANGE.begin
+        User::username_length.end.should == User::GLOBAL_USERNAME_LENGTH_RANGE.end 
+      end
+    end
   end
 
   describe 'delete posts' do
@@ -422,7 +450,7 @@ describe User do
   end
 
   describe 'username format' do
-    it "should always be 3 chars or longer" do
+    it "should be #{SiteSetting.min_username_length} chars or longer" do
       @user = Fabricate.build(:user)
       @user.username = 'ss'
       @user.save.should == false