bpo-46421: Fix unittest filename evaluation when called as a module

Lib/unittest/loader.py

@@ -122,7 +122,7 @@ def loadTestsFromName(self, name, module=None):
 
         The method optionally resolves the names relative to a given module.
         """
-        parts = name.split('.')
+        parts = name.lstrip('.').split('.')
         error_case, error_message = None, None
         if module is None:
             parts_copy = parts[:]

Misc/ACKS

@@ -1985,6 +1985,7 @@ Masazumi Yoshikawa
 Arnaud Ysmal
 Bernard Yue
 Moshe Zadka
+Bader Zaidan
 Elias Zamaria
 Milan Zamazal
 Artur Zaprzala

Misc/NEWS.d/next/Library/2022-01-18-01-29-38.bpo-46421.9LdmNr.rst

@@ -0,0 +1,3 @@
+Fix a unittest issue where if the command was invoked as ``python -m
+unittest`` and the filename(s) began with a dot (.), a ``ValueError`` is
+returned.