diff --git a/telebot/formatting.py b/telebot/formatting.py
index 73f737fd4..bfb278f73 100644
--- a/telebot/formatting.py
+++ b/telebot/formatting.py
@@ -423,13 +423,13 @@ def format_entity(entity, content):
         #     username = content[1:]  # Remove @ symbol
         #     return f"<a href=\"https://t.me/{username}\">{content}</a>"
         elif entity_type == "text_link" and hasattr(entity, 'url'):
-            return _subs["text_link"].format(url=entity.url, text=content)
+            return _subs["text_link"].format(url=escape_html(entity.url), text=content)
         elif entity_type == "custom_emoji" and hasattr(entity, 'custom_emoji_id'):
             return _subs["custom_emoji"].format(custom_emoji_id=entity.custom_emoji_id, text=content)
         elif entity_type == "date_time" and hasattr(entity, 'unix_time') and hasattr(entity, 'date_time_format'):
-            return _subs["date_time"].format(unix=entity.unix_time, date_time_format=entity.date_time_format, text=content)
+            return _subs["date_time"].format(unix_time=entity.unix_time, date_time_format=entity.date_time_format, text=content)
         elif entity_type == "pre" and hasattr(entity, 'language') and entity.language:
-            return f"<pre><code class=\"language-{entity.language}\">{content}</code></pre>"
+            return f"<pre><code class=\"language-{escape_html(entity.language)}\">{content}</code></pre>"
         elif entity_type in _subs:
             template = _subs[entity_type]
             return template.format(text=content)
diff --git a/telebot/util.py b/telebot/util.py
index bbb9b98af..181898230 100644
--- a/telebot/util.py
+++ b/telebot/util.py
@@ -279,6 +279,7 @@ def extract_arguments(text: str) -> Union[str, None]:
     :rtype: :obj:`str` or :obj:`None`
     """
     regexp = re.compile(r"/\w*(@\w*)*\s*([\s\S]*)", re.IGNORECASE)
+    if text is None: return None
     result = regexp.match(text)
     return result.group(2) if is_command(text) else None
 
@@ -357,7 +358,7 @@ def _text_before_last(substr: str) -> str:
 
     parts = []
     while True:
-        if len(text) < chars_per_string:
+        if len(text) <= chars_per_string:
             parts.append(text)
             return parts
 
diff --git a/tests/test_formatting.py b/tests/test_formatting.py
index eb0eabdfb..68319e86d 100644
--- a/tests/test_formatting.py
+++ b/tests/test_formatting.py
@@ -4,7 +4,8 @@
 
 from html.parser import HTMLParser
 
-from telebot.formatting import hpre
+from telebot import types
+from telebot.formatting import apply_html_entities, hpre
 
 
 class AttributeCollector(HTMLParser):
@@ -35,3 +36,41 @@ def test_hpre_language_cannot_add_attributes():
 
 def test_hpre_still_escapes_content():
     assert hpre("<b>", language="python") == '<pre><code class="python">&lt;b&gt;</code></pre>'
+
+
+def test_apply_html_entities_date_time():
+    # used to raise KeyError: 'unix_time' because the template was formatted with
+    # unix= while it declares {unix_time}
+    entity = types.MessageEntity(
+        type="date_time", offset=11, length=5,
+        unix_time=1735689600, date_time_format="r"
+    )
+    assert apply_html_entities("Meeting at 10:00", [entity]) == (
+        'Meeting at <tg-time unix="1735689600" format="r">10:00</tg-time>'
+    )
+
+
+def test_apply_html_entities_escapes_link_url():
+    entity = types.MessageEntity(
+        type="text_link", offset=0, length=4, url='https://x.test/?a="b'
+    )
+    parser = AttributeCollector()
+    parser.feed(apply_html_entities("link rest", [entity]))
+    assert parser.tags == [("a", [("href", 'https://x.test/?a="b')])]
+
+
+def test_apply_html_entities_escapes_pre_language():
+    entity = types.MessageEntity(
+        type="pre", offset=0, length=4, language='py" onload="x'
+    )
+    parser = AttributeCollector()
+    parser.feed(apply_html_entities("code rest", [entity]))
+    assert parser.tags == [
+        ("pre", []),
+        ("code", [("class", 'language-py" onload="x')]),
+    ]
+
+
+def test_apply_html_entities_still_escapes_content():
+    entity = types.MessageEntity(type="bold", offset=0, length=4)
+    assert apply_html_entities("a<b> c", [entity]) == "<b>a&lt;b&gt;</b> c"
diff --git a/tests/test_util.py b/tests/test_util.py
new file mode 100644
index 000000000..50220f333
--- /dev/null
+++ b/tests/test_util.py
@@ -0,0 +1,38 @@
+from telebot import util
+
+
+def test_smart_split_exact_multiple_has_no_trailing_empty_part():
+    # A chunk boundary landing exactly on the limit used to append an empty part.
+    for size in (1, 2, 3, 4, 10):
+        for chunks in (1, 2, 3):
+            text = "a" * (size * chunks)
+            assert util.smart_split(text, size) == ["a" * size] * chunks
+
+
+def test_smart_split_short_text():
+    assert util.smart_split("abc", 3) == ["abc"]
+    assert util.smart_split("abcde", 3) == ["abc", "de"]
+    assert util.smart_split("", 3) == [""]
+
+
+def test_smart_split_prefers_newline_then_space():
+    assert util.smart_split("one two\nthree four", 10) == ["one two\n", "three four"]
+    assert util.smart_split("one two three", 8) == ["one two ", "three"]
+
+
+def test_smart_split_caps_at_max_message_length():
+    parts = util.smart_split("a" * (util.MAX_MESSAGE_LENGTH * 2), util.MAX_MESSAGE_LENGTH * 5)
+    assert [len(p) for p in parts] == [util.MAX_MESSAGE_LENGTH] * 2
+
+
+def test_extract_arguments_accepts_none():
+    # message.text is None for non-text messages
+    assert util.extract_arguments(None) is None  # type: ignore[arg-type]
+    assert util.extract_command(None) is None  # type: ignore[arg-type]
+
+
+def test_extract_arguments_values():
+    assert util.extract_arguments("/get name") == "name"
+    assert util.extract_arguments("/get") == ""
+    assert util.extract_arguments("/get@bot name") == "name"
+    assert util.extract_arguments("hello") is None