diff --git a/tests/vim.py b/tests/vim.py
index 5561fff4..89beb9c3 100644
--- a/tests/vim.py
+++ b/tests/vim.py
@@ -1,10 +1,10 @@
 # vim:fileencoding=utf-8:noet
 _log = []
-_g = {}
+vars = {}
 _window = 0
 _mode = 'n'
 _buf_purge_events = set()
-_options = {
+options = {
 	'paste': 0,
 	'ambiwidth': 'single',
 }
@@ -151,7 +151,7 @@ def command(cmd):
 	if cmd.startswith('let g:'):
 		import re
 		varname, value = re.compile(r'^let g:(\w+)\s*=\s*(.*)').match(cmd).groups()
-		_g[varname] = value
+		vars[varname] = value
 	elif cmd.startswith('hi '):
 		sp = cmd.split()
 		_highlights[sp[1]] = sp[2:]
@@ -162,9 +162,9 @@ def command(cmd):
 @_vim
 def eval(expr):
 	if expr.startswith('g:'):
-		return _g[expr[2:]]
+		return vars[expr[2:]]
 	elif expr.startswith('&'):
-		return _options[expr[1:]]
+		return options[expr[1:]]
 	elif expr.startswith('PowerlineRegisterCachePurgerEvent'):
 		_buf_purge_events.add(expr[expr.find('"') + 1:expr.rfind('"') - 1])
 		return "0"
@@ -174,7 +174,7 @@ def eval(expr):
 @_vim
 def bindeval(expr):
 	if expr == 'g:':
-		return _g
+		return vars
 	import re
 	match = re.compile(r'^function\("([^"\\]+)"\)$').match(expr)
 	if match:
@@ -201,10 +201,10 @@ def _emul_getbufvar(bufnr, varname):
 		if bufnr not in buffers:
 			return ''
 		try:
-			return _buf_options[bufnr][varname[1:]]
+			return buffers[bufnr].options[varname[1:]]
 		except KeyError:
 			try:
-				return _options[varname[1:]]
+				return options[varname[1:]]
 			except KeyError:
 				return ''
 	raise NotImplementedError
@@ -213,12 +213,12 @@ def _emul_getbufvar(bufnr, varname):
 @_vim
 @_str_func
 def _emul_getwinvar(winnr, varname):
-	return _win_scopes[winnr][varname]
+	return windows[winnr].vars[varname]
 
 
 @_vim
 def _emul_setwinvar(winnr, varname, value):
-	_win_scopes[winnr][varname] = value
+	windows[winnr].vars[varname] = value
 
 
 @_vim
@@ -262,7 +262,7 @@ def _emul_bufnr(expr):
 @_vim
 def _emul_exists(varname):
 	if varname.startswith('g:'):
-		return varname[2:] in _g
+		return varname[2:] in vars
 	raise NotImplementedError
 
 
@@ -273,10 +273,9 @@ def _emul_line2byte(line):
 		return sum((len(s) for s in buflines)) + 1
 	raise NotImplementedError
 
+
 _window_ids = [None]
 _window_id = 0
-_win_scopes = [None]
-_win_options = [None]
 
 
 class _Window(object):
@@ -295,15 +294,13 @@ class _Window(object):
 		windows.append(self)
 		_window_id += 1
 		_window_ids.append(_window_id)
-		_win_scopes.append({})
-		_win_options.append({})
+		self.options = {}
+		self.vars = {}
 
 	def __repr__(self):
 		return '<window ' + str(windows.index(self)) + '>'
 
 
-_buf_scopes = {}
-_buf_options = {}
 _buf_lines = {}
 _undostate = {}
 _undo_written = {}
@@ -317,8 +314,8 @@ class _Buffer(object):
 		bufnr = _last_bufnr
 		self.number = bufnr
 		self.name = os.path.abspath(name) if name else None
-		_buf_scopes[bufnr] = {}
-		_buf_options[bufnr] = {
+		self.vars = {}
+		self.options = {
 			'modified': 0,
 			'readonly': 0,
 			'fileformat': 'unix',
@@ -337,13 +334,13 @@ class _Buffer(object):
 		return _buf_lines[self.number][line]
 
 	def __setitem__(self, line, value):
-		_buf_options[self.number]['modified'] = 1
+		self.options['modified'] = 1
 		_buf_lines[self.number][line] = value
 		from copy import copy
 		_undostate[self.number].append(copy(_buf_lines[self.number]))
 
 	def __setslice__(self, *args):
-		_buf_options[self.number]['modified'] = 1
+		self.options['modified'] = 1
 		_buf_lines[self.number].__setslice__(*args)
 		from copy import copy
 		_undostate[self.number].append(copy(_buf_lines[self.number]))
@@ -359,12 +356,10 @@ class _Buffer(object):
 
 	def __del__(self):
 		bufnr = self.number
-		if _buf_options:
-			_buf_options.pop(bufnr)
+		if _buf_lines:
 			_buf_lines.pop(bufnr)
 			_undostate.pop(bufnr)
 			_undo_written.pop(bufnr)
-			_buf_scopes.pop(bufnr)
 
 
 class _Current(object):
@@ -436,8 +431,9 @@ def _undo():
 		return
 	_undostate[_buffer()].pop(-1)
 	_buf_lines[_buffer()] = _undostate[_buffer()][-1]
+	buf = current.buffer
 	if _undo_written[_buffer()] == len(_undostate[_buffer()]):
-		_buf_options[_buffer()]['modified'] = 0
+		buf.options['modified'] = 0
 
 
 @_vim
@@ -468,8 +464,6 @@ def _split():
 @_vim
 def _del_window(winnr):
 	win = windows.pop(winnr - 1)
-	_win_scopes.pop(winnr)
-	_win_options.pop(winnr)
 	_window_ids.pop(winnr)
 	return win
 
@@ -525,7 +519,7 @@ def _get_buffer():
 
 @_vim
 def _set_bufoption(option, value, bufnr=None):
-	_buf_options[bufnr or _buffer()][option] = value
+	buffers[bufnr or _buffer()].options[option] = value
 	if option == 'filetype':
 		_launch_event('FileType')
 
@@ -565,11 +559,11 @@ class _WithBufOption(object):
 		self.new = new
 
 	def __enter__(self):
-		self.bufnr = _buffer()
-		self.old = _set_dict(_buf_options[self.bufnr], self.new, _set_bufoption)[0]
+		self.buffer = buffers[_buffer()]
+		self.old = _set_dict(self.buffer.options, self.new, _set_bufoption)[0]
 
 	def __exit__(self, *args):
-		_buf_options[self.bufnr].update(self.old)
+		self.buffer.options.update(self.old)
 
 
 class _WithMode(object):
@@ -632,8 +626,8 @@ def _with(key, *args, **kwargs):
 	elif key == 'bufoptions':
 		return _WithBufOption(**kwargs)
 	elif key == 'options':
-		return _WithDict(_options, **kwargs)
+		return _WithDict(options, **kwargs)
 	elif key == 'globals':
-		return _WithDict(_g, **kwargs)
+		return _WithDict(vars, **kwargs)
 	elif key == 'split':
 		return _WithSplit()