download test dependency if needed

Author: vimark1

tests/run.sh

@@ -1,6 +1,11 @@
 #!/bin/sh
 : "${VIM_EXE:=vim}"
 
+# download test dependency if needed
+if [[ ! -d "./vader.vim" ]]; then
+  git clone https://github.com/junegunn/vader.vim.git vader.vim
+fi
+
 # If nvim is available in PATH, then we prefer to use nvim
 # since it works better with nodemon
 if hash nvim 2>/dev/null ; then