Replace LazyString implementation with a modified collection.UserString

src/jinjax/html_attrs.py

@@ -1,6 +1,9 @@
 import re
+from collections import UserString
+from functools import cached_property
 from typing import Any
 
+
 CLASS_KEY = "class"
 CLASS_ALT_KEY = "classes"
 CLASS_KEYS = (CLASS_KEY, CLASS_ALT_KEY)
@@ -21,24 +24,23 @@ def quote(text: str) -> str:
     return f'"{text}"'
 
 
-class LazyString:
-    """The string representation of an object, but lazily casted to str."""
+class LazyString(UserString):
+    """Behave like regular strings, but the actual casting of the initial value
+    is deferred until the value is actually required."""
 
-    def __init__(self, value: Any) -> None:
-        self.value = value
+    __slots__ = ("_seq",)
 
-    def __str__(self) -> str:
-        if not hasattr(self, "_value_str"):
-            self._value_str = str(self.value)
-        return self._value_str
+    def __init__(self, seq):
+        self._seq = seq
 
-    def __eq__(self, other: Any) -> bool:
-        return str(self) == other
+    @cached_property
+    def data(self):
+        return str(self._seq)
 
 
 class HTMLAttrs:
     def __init__(self, attrs) -> None:
-        attributes: "dict[str, str]" = {}
+        attributes: "dict[str, str|LazyString]" = {}
         properties: "set[str]" = set()
 
         class_names = split(" ".join([

tests/test_html_attrs.py

@@ -168,3 +168,80 @@ def __str__(self):
 
     with pytest.raises(RuntimeError):
         attrs.render()
+
+
+def test_additional_attributes_lazily_evaluated_has_string_methods():
+    class TestObject:
+        def __str__(self):
+            return 'test'
+
+    attrs = HTMLAttrs({"some_object": TestObject()})
+
+    assert attrs["some_object"].__str__
+    assert attrs["some_object"].__repr__
+    assert attrs["some_object"].__int__
+    assert attrs["some_object"].__float__
+    assert attrs["some_object"].__complex__
+    assert attrs["some_object"].__hash__
+    assert attrs["some_object"].__eq__
+    assert attrs["some_object"].__lt__
+    assert attrs["some_object"].__le__
+    assert attrs["some_object"].__gt__
+    assert attrs["some_object"].__ge__
+    assert attrs["some_object"].__contains__
+    assert attrs["some_object"].__len__
+    assert attrs["some_object"].__getitem__
+    assert attrs["some_object"].__add__
+    assert attrs["some_object"].__radd__
+    assert attrs["some_object"].__mul__
+    assert attrs["some_object"].__mod__
+    assert attrs["some_object"].__rmod__
+    assert attrs["some_object"].capitalize
+    assert attrs["some_object"].casefold
+    assert attrs["some_object"].center
+    assert attrs["some_object"].count
+    assert attrs["some_object"].removeprefix
+    assert attrs["some_object"].removesuffix
+    assert attrs["some_object"].encode
+    assert attrs["some_object"].endswith
+    assert attrs["some_object"].expandtabs
+    assert attrs["some_object"].find
+    assert attrs["some_object"].format
+    assert attrs["some_object"].format_map
+    assert attrs["some_object"].index
+    assert attrs["some_object"].isalpha
+    assert attrs["some_object"].isalnum
+    assert attrs["some_object"].isascii
+    assert attrs["some_object"].isdecimal
+    assert attrs["some_object"].isdigit
+    assert attrs["some_object"].isidentifier
+    assert attrs["some_object"].islower
+    assert attrs["some_object"].isnumeric
+    assert attrs["some_object"].isprintable
+    assert attrs["some_object"].isspace
+    assert attrs["some_object"].istitle
+    assert attrs["some_object"].isupper
+    assert attrs["some_object"].join
+    assert attrs["some_object"].ljust
+    assert attrs["some_object"].lower
+    assert attrs["some_object"].lstrip
+    assert attrs["some_object"].partition
+    assert attrs["some_object"].replace
+    assert attrs["some_object"].rfind
+    assert attrs["some_object"].rindex
+    assert attrs["some_object"].rjust
+    assert attrs["some_object"].rpartition
+    assert attrs["some_object"].rstrip
+    assert attrs["some_object"].split
+    assert attrs["some_object"].rsplit
+    assert attrs["some_object"].splitlines
+    assert attrs["some_object"].startswith
+    assert attrs["some_object"].strip
+    assert attrs["some_object"].swapcase
+    assert attrs["some_object"].title
+    assert attrs["some_object"].translate
+    assert attrs["some_object"].upper
+    assert attrs["some_object"].zfill
+
+    assert attrs["some_object"].upper() == 'TEST'
+    assert attrs["some_object"].title() == 'Test'