From 6a9f58986d29ec2918a10e600cf8e84b84eac54f Mon Sep 17 00:00:00 2001
From: Stephan Kulow <stephan.kulow@siemens.com>
Date: Fri, 18 Jul 2025 07:15:43 +0200
Subject: [PATCH] Fix pascalcase stealing first character from boundaries

By picking the first character out of the input, an artificial
boundary is created between first and second character. Fixed by
creating a pascalcase specific boundary checking if there is no
previous character.
---
 caseconverter/boundaries.py  |  2 +-
 caseconverter/pascal.py      | 13 +++++++++++--
 caseconverter/pascal_test.py |  1 +
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/caseconverter/boundaries.py b/caseconverter/boundaries.py
index 783906c..0e9d5d6 100644
--- a/caseconverter/boundaries.py
+++ b/caseconverter/boundaries.py
@@ -99,7 +99,7 @@ def __init__(self, join_char=""):
         self._join_char = join_char
 
     def is_boundary(self, pc, c):
-        return pc != None and pc.isalpha() and pc.isupper() and c.isupper()
+        return pc is not None and pc.isalpha() and pc.isupper() and c.isupper()
 
     def handle(self, pc, cc, input_buffer, output_buffer):
         output_buffer.write(cc)
diff --git a/caseconverter/pascal.py b/caseconverter/pascal.py
index 79f9655..57bebe9 100644
--- a/caseconverter/pascal.py
+++ b/caseconverter/pascal.py
@@ -1,16 +1,25 @@
 from .caseconverter import CaseConverter
 from .boundaries import (
+    BoundaryHandler,
     OnDelimeterUppercaseNext,
     OnUpperPrecededByLowerAppendUpper,
     OnUpperPrecededByUpperAppendCurrent,
 )
 
+class OnFirstCharUpper(BoundaryHandler):
+    """Boundary handler that ensures the first character is uppercase."""
+
+    def is_boundary(self, pc, c):
+        return pc is None
+
+    def handle(self, pc, cc, input_buffer, output_buffer):
+        output_buffer.write(cc.upper())
+
 
 class Pascal(CaseConverter):
-    def init(self, input_buffer, output_buffer):
-        output_buffer.write(input_buffer.read(1).upper())
 
     def define_boundaries(self):
+        self.add_boundary_handler(OnFirstCharUpper())
         self.add_boundary_handler(OnDelimeterUppercaseNext(self.delimiters()))
         self.add_boundary_handler(OnUpperPrecededByLowerAppendUpper())
         self.add_boundary_handler(OnUpperPrecededByUpperAppendCurrent())
diff --git a/caseconverter/pascal_test.py b/caseconverter/pascal_test.py
index bd28da3..e4756fb 100644
--- a/caseconverter/pascal_test.py
+++ b/caseconverter/pascal_test.py
@@ -31,6 +31,7 @@
         # Alternating character cases
         ("heLlo WoRld", "HeLloWoRld"),
         ("helloWORLD", "HelloWORLD"),
+        ("HELLOWorld", "HELLOWorld"),
     ],
 )
 def test_pascal_with_default_args(input, output):