fix: Allow end=None in patch operation

- Removed the end parameter validation from EditPatch model
- Now end=None means the patch will be applied to the end of file
- Added test case for end=None scenario
- Updated test_models.py to reflect the new behavior

Author: tumf

src/mcp_text_editor/models.py

@@ -35,14 +35,10 @@ class EditPatch(BaseModel):
 
     @model_validator(mode="after")
     def validate_end_line(self) -> "EditPatch":
-        """Validate that end line is present when not in append mode."""
+        """Validate that range_hash is set."""
         # range_hash must be explicitly set
         if self.range_hash is None:
             raise ValueError("range_hash is required")
-
-        # For modifications (non-empty range_hash), end is required
-        if self.range_hash != "" and self.end is None:
-            raise ValueError("end line is required when not in append mode")
         return self
 
 

tests/test_models.py

@@ -74,12 +74,6 @@ def test_edit_patch():
     with pytest.raises(ValidationError):
         EditPatch()
 
-    # Test validation error - missing end in modification mode
-    with pytest.raises(
-        ValueError, match="end line is required when not in append mode"
-    ):
-        EditPatch(start=1, contents="content", range_hash="somehash")
-
 
 def test_edit_file_operation():
     """Test EditFileOperation model."""