diff --git a/comtypes/test/find_memleak.py b/comtypes/test/find_memleak.py
index d27e68e1..88cf7f07 100644
--- a/comtypes/test/find_memleak.py
+++ b/comtypes/test/find_memleak.py
@@ -27,8 +27,14 @@ def dump(self):
             print(n, getattr(self, n) / 1e6)
 
 
+_psapi = WinDLL("psapi")
+
+_GetProcessMemoryInfo = _psapi.GetProcessMemoryInfo
+_GetProcessMemoryInfo.argtypes = [HANDLE, POINTER(PROCESS_MEMORY_COUNTERS), DWORD]
+_GetProcessMemoryInfo.restype = BOOL
+
 try:
-    windll.psapi.GetProcessMemoryInfo.argtypes = (
+    _GetProcessMemoryInfo.argtypes = (
         HANDLE,
         POINTER(PROCESS_MEMORY_COUNTERS),
         DWORD,
@@ -43,7 +49,7 @@ def find_memleak(func, loops=None):
     def wss():
         # Return the working set size (memory used by process)
         pmi = PROCESS_MEMORY_COUNTERS()
-        if not windll.psapi.GetProcessMemoryInfo(-1, byref(pmi), sizeof(pmi)):
+        if not _GetProcessMemoryInfo(-1, byref(pmi), sizeof(pmi)):
             raise WinError()
         return pmi.WorkingSetSize
 
diff --git a/comtypes/test/test_ie.py b/comtypes/test/test_ie.py
index dcd112f1..1e5c6095 100644
--- a/comtypes/test/test_ie.py
+++ b/comtypes/test/test_ie.py
@@ -1,5 +1,6 @@
 import unittest as ut
-from ctypes import Structure, c_long, c_uint, c_ulong
+from ctypes import POINTER, Structure, WinDLL, byref, c_long, c_uint, c_ulong
+from ctypes.wintypes import BOOL, HWND, LPLONG, UINT
 
 from comtypes.client import CreateObject, GetEvents
 
@@ -58,14 +59,26 @@ class MSG(Structure):
 
 
 def PumpWaitingMessages():
-    from ctypes import byref, windll
+    _user32 = WinDLL("user32")
+
+    _PeekMessageA = _user32.PeekMessageA
+    _PeekMessageA.argtypes = [POINTER(MSG), HWND, UINT, UINT, UINT]
+    _PeekMessageA.restype = BOOL
+
+    _TranslateMessage = _user32.TranslateMessage
+    _TranslateMessage.argtypes = [POINTER(MSG)]
+    _TranslateMessage.restype = BOOL
+
+    LRESULT = LPLONG
+    _DispatchMessageA = _user32.DispatchMessageA
+    _DispatchMessageA.argtypes = [POINTER(MSG)]
+    _DispatchMessageA.restype = LRESULT
 
-    user32 = windll.user32
     msg = MSG()
     PM_REMOVE = 0x0001
-    while user32.PeekMessageA(byref(msg), 0, 0, 0, PM_REMOVE):
-        user32.TranslateMessage(byref(msg))
-        user32.DispatchMessageA(byref(msg))
+    while _PeekMessageA(byref(msg), 0, 0, 0, PM_REMOVE):
+        _TranslateMessage(byref(msg))
+        _DispatchMessageA(byref(msg))
 
 
 class Test(ut.TestCase):
diff --git a/comtypes/test/test_imfattributes.py b/comtypes/test/test_imfattributes.py
index c3c2dd03..ecebdc25 100644
--- a/comtypes/test/test_imfattributes.py
+++ b/comtypes/test/test_imfattributes.py
@@ -1,7 +1,7 @@
 import contextlib
 import unittest as ut
 
-from ctypes import POINTER, pointer, windll
+from ctypes import HRESULT, POINTER, WinDLL, c_uint32, pointer
 from comtypes import GUID
 import comtypes.client
 
@@ -12,8 +12,18 @@ def test_imfattributes(self):
             comtypes.client.GetModule("msvidctl.dll")
         from comtypes.gen import MSVidCtlLib
 
+        _mfplat = WinDLL("mfplat")
+
+        UINT32 = c_uint32
+        _MFCreateAttributes = _mfplat.MFCreateAttributes
+        _MFCreateAttributes.argtypes = [
+            POINTER(POINTER(MSVidCtlLib.IMFAttributes)),
+            UINT32,
+        ]
+        _MFCreateAttributes.restype = HRESULT
+
         imf_attrs = POINTER(MSVidCtlLib.IMFAttributes)()
-        hres = windll.mfplat.MFCreateAttributes(pointer(imf_attrs), 2)
+        hres = _MFCreateAttributes(pointer(imf_attrs), 2)
         self.assertEqual(hres, 0)
 
         MF_TRANSCODE_ADJUST_PROFILE = GUID("{9c37c21b-060f-487c-a690-80d7f50d1c72}")