Load plugin.
  
    $ antigen-bundle $PLUGIN_DIR
    Cloning into '.+?'\.\.\. (re)
    done.
    $ hehe
    hehe
  
  Update the plugin.
  
    $ cat > $PLUGIN_DIR/aliases.zsh <<EOF
    > alias hehe='echo hehe, updated'
    > EOF
    $ pg commit -am 'Updated message'
    \[master [a-f0-9]{7}\] Updated message (re)
     1 file changed, 1 insertion(+), 1 deletion(-)
  
  Run antigen's update.
  
    $ antigen-update
    **** Pulling */test-plugin (glob)
    From */test-plugin (glob)
       ???????..???????  master     -> origin/master (glob)
    Updating ???????..??????? (glob)
    Fast-forward
     aliases.zsh |    2 +-
     1 file changed, 1 insertion(+), 1 deletion(-)
    Updated from ??????? to ???????. (glob)
    ??????? Updated message (glob)
     aliases.zsh |    2 +-
     1 file changed, 1 insertion(+), 1 deletion(-)
    
  
  Confirm there is still only one repository.
  
    $ ls $ADOTDIR/repos | wc -l
    1
  
  The new alias should not activate.
  
    $ hehe
    hehe
  
  Run update again, with no changes in the origin repo.
  
    $ antigen-update
    **** Pulling */test-plugin (glob)
    Already up-to-date.