DO-NOT-MERGE: Explore reasons for ctypes test failure

Lib/test/__main__.py

@@ -1,2 +1,52 @@
-from test.libregrtest import main
-main()
+import os
+import sys
+
+try:
+    import winreg
+except ImportError:
+    sys.exit(0)
+
+found = False
+for d in os.environ['PATH'].split(os.pathsep):
+    print('Checking', d)
+    try:
+        with os.scandir(d) as sd:
+            for de in sd:
+                if de.name == '_sqlite3.dll' and de.is_file():
+                    print('Found _sqlite3.dll at', de.path)
+                    found = True
+    except OSError as e:
+        print(e)
+
+try:
+    value = winreg.QueryValueEx(
+        winreg.OpenKeyEx(
+            winreg.HKEY_LOCAL_MACHINE,
+            'SYSTEM\\CurrentControlSet\\Control\\Session Manager'
+        ),
+        'CWDIllegalInDllSearch'
+    )
+except FileNotFoundError:
+    print('CWDIllegalInDllSearch not set')
+else:
+    print('CWDIllegalInDllSearch set to', value)
+    found = True
+
+base_key = winreg.OpenKeyEx(
+    winreg.HKEY_LOCAL_MACHINE,
+    'Software\\Microsoft\\Windows NT\\CurrentVersion\\Image File Execution Options'
+)
+for i in range(winreg.QueryInfoKey(base_key)[0]):
+    sub_key_name = winreg.EnumKey(base_key, i)
+    print(sub_key_name)
+    if 'py' not in sub_key_name:
+        continue
+    sub_key = winreg.OpenKeyEx(base_key, sub_key_name)
+    for j in range(winreg.QueryInfoKey(sub_key)[1]):
+        name, value, type = winreg.EnumValue(sub_key, j)
+        if 'CWD' in name:
+            print(name, value, type)
+            found = True
+
+if found:
+    raise FileExistsError('Found it')