fix: recognize single-letter suffix_not_acronyms (e.g. 'V') in suffix-comma format (closes #136)

Roman numeral suffixes like 'V' are single uppercase letters, which the
initial regex also matches. In suffix-comma format ("John Ingram, V") the
post-comma position is unambiguous, so the initial guard should not block
recognition. Add are_suffixes_after_comma() that bypasses the initial check
for suffix_not_acronyms members and use it at the suffix-comma detection site,
leaving is_suffix() unchanged for the no-comma path where 'V' mid-name should
still be treated as an initial.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: derek73

nameparser/parser.py

@@ -487,6 +487,21 @@ def are_suffixes(self, pieces: Iterable[str]) -> bool:
                 return False
         return True
 
+    def are_suffixes_after_comma(self, pieces: Iterable[str]) -> bool:
+        """Like are_suffixes but suffix_not_acronyms members are always
+        recognized, even when they look like single-letter initials.
+
+        Used when detecting suffix-comma format (e.g. "John Ingram, V") where
+        the post-comma position is unambiguous: a single uppercase roman
+        numeral like 'V' is definitionally a suffix there, not an initial.
+        """
+        for piece in pieces:
+            if lc(piece) in self.C.suffix_not_acronyms:
+                continue
+            if not self.is_suffix(piece):
+                return False
+        return True
+
     def is_rootname(self, piece: str) -> bool:
         """
         Is not a known title, suffix or prefix. Just first, middle, last names.
@@ -686,7 +701,7 @@ def parse_full_name(self) -> None:
 
             post_comma_pieces = self.parse_pieces(parts[1].split(' '), 1)
 
-            if self.are_suffixes(parts[1].split(' ')) \
+            if self.are_suffixes_after_comma(parts[1].split(' ')) \
                     and len(parts[0].split(' ')) > 1:
 
                 # suffix comma:

tests/test_suffixes.py

@@ -34,6 +34,15 @@ def test_two_suffixes_lastname_comma_format(self) -> None:
         # NOTE: this adds a comma when the original format did not have one.
         self.m(hn.suffix, "Jr., MD", hn)
 
+    def test_roman_numeral_v_suffix_comma_format(self) -> None:
+        # 'V' is a single uppercase letter, so it was incorrectly matched as an
+        # initial and not recognized as a suffix (issue #136)
+        hn = HumanName("John W. Ingram, V")
+        self.m(hn.first, "John", hn)
+        self.m(hn.middle, "W.", hn)
+        self.m(hn.last, "Ingram", hn)
+        self.m(hn.suffix, "V", hn)
+
     def test_two_suffixes_suffix_comma_format(self) -> None:
         hn = HumanName("Franklin Washington, Jr. MD")
         self.m(hn.first, "Franklin", hn)