diff --git a/pynvim/msgpack_rpc/event_loop/asyncio.py b/pynvim/msgpack_rpc/event_loop/asyncio.py
index cea7298c..a506c927 100644
--- a/pynvim/msgpack_rpc/event_loop/asyncio.py
+++ b/pynvim/msgpack_rpc/event_loop/asyncio.py
@@ -14,7 +14,7 @@
 import sys
 from collections import deque
 from signal import Signals
-from typing import Any, Callable, Deque, List
+from typing import Any, Callable, Deque, List, Optional
 
 from pynvim.msgpack_rpc.event_loop.base import BaseEventLoop
 
@@ -37,6 +37,8 @@ class AsyncioEventLoop(BaseEventLoop, asyncio.Protocol,
     """`BaseEventLoop` subclass that uses `asyncio` as a backend."""
 
     _queued_data: Deque[bytes]
+    if os.name != 'nt':
+        _child_watcher: Optional['asyncio.AbstractChildWatcher']
 
     def connection_made(self, transport):
         """Used to signal `asyncio.Protocol` of a successful connection."""
@@ -78,6 +80,7 @@ def _init(self) -> None:
         self._queued_data = deque()
         self._fact = lambda: self
         self._raw_transport = None
+        self._child_watcher = None
 
     def _connect_tcp(self, address: str, port: int) -> None:
         coroutine = self._loop.create_connection(self._fact, address, port)
@@ -145,6 +148,9 @@ def _close(self) -> None:
         if self._raw_transport is not None:
             self._raw_transport.close()
         self._loop.close()
+        if self._child_watcher is not None:
+            self._child_watcher.close()
+            self._child_watcher = None
 
     def _threadsafe_call(self, fn: Callable[[], Any]) -> None:
         self._loop.call_soon_threadsafe(fn)
diff --git a/test/conftest.py b/test/conftest.py
index 85e56ab6..9bbd5295 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -1,5 +1,9 @@
+"""Configs for pytest."""
+
+import gc
 import json
 import os
+from typing import Generator
 
 import pytest
 
@@ -9,7 +13,10 @@
 
 
 @pytest.fixture
-def vim() -> pynvim.Nvim:
+def vim() -> Generator[pynvim.Nvim, None, None]:
+    """Create an embedded, sub-process Nvim fixture instance."""
+    editor: pynvim.Nvim
+
     child_argv = os.environ.get('NVIM_CHILD_ARGV')
     listen_address = os.environ.get('NVIM_LISTEN_ADDRESS')
     if child_argv is None and listen_address is None:
@@ -28,4 +35,13 @@ def vim() -> pynvim.Nvim:
         assert listen_address is not None and listen_address != ''
         editor = pynvim.attach('socket', path=listen_address)
 
-    return editor
+    try:
+        yield editor
+
+    finally:
+        # Ensure all internal resources (pipes, transports, etc.) are always
+        # closed properly. Otherwise, during GC finalizers (__del__) will raise
+        # "Event loop is closed" error.
+        editor.close()
+
+        gc.collect()  # force-run GC, to early-detect potential leakages
diff --git a/test/test_host.py b/test/test_host.py
index 016d48b7..18cff327 100644
--- a/test/test_host.py
+++ b/test/test_host.py
@@ -11,15 +11,19 @@
 
 def test_host_imports(vim):
     h = ScriptHost(vim)
-    assert h.module.__dict__['vim']
-    assert h.module.__dict__['vim'] == h.legacy_vim
-    assert h.module.__dict__['sys']
+    try:
+        assert h.module.__dict__['vim']
+        assert h.module.__dict__['vim'] == h.legacy_vim
+        assert h.module.__dict__['sys']
+    finally:
+        h.teardown()
 
 
 def test_host_import_rplugin_modules(vim):
     # Test whether a Host can load and import rplugins (#461).
     # See also $VIMRUNTIME/autoload/provider/pythonx.vim.
     h = Host(vim)
+
     plugins: Sequence[str] = [  # plugin paths like real rplugins
         os.path.join(__PATH__, "./fixtures/simple_plugin/rplugin/python3/simple_nvim.py"),
         os.path.join(__PATH__, "./fixtures/module_plugin/rplugin/python3/mymodule/"),
@@ -56,7 +60,10 @@ def test_host_async_error(vim):
 
 def test_legacy_vim_eval(vim):
     h = ScriptHost(vim)
-    assert h.legacy_vim.eval('1') == '1'
-    assert h.legacy_vim.eval('v:null') is None
-    assert h.legacy_vim.eval('v:true') is True
-    assert h.legacy_vim.eval('v:false') is False
+    try:
+        assert h.legacy_vim.eval('1') == '1'
+        assert h.legacy_vim.eval('v:null') is None
+        assert h.legacy_vim.eval('v:true') is True
+        assert h.legacy_vim.eval('v:false') is False
+    finally:
+        h.teardown()