refactor (response): remove deprecated attributes (#2317)

* refactor (response): Remove deprecated attributes

* refactor (response): Organize imports with ruff check --fix

* test (response): Refactor test_response_set_stream test

* test (response): Fix set stream test

* test (response): Improve assertion

falcon/response.py

@@ -41,11 +41,6 @@
 from falcon.util.uri import encode_check_escaped as uri_encode
 from falcon.util.uri import encode_value_check_escaped as uri_encode_value
 
-_STREAM_LEN_REMOVED_MSG = (
-    'The deprecated stream_len property was removed in Falcon 3.0. '
-    'Please use Response.set_stream() or Response.content_length instead.'
-)
-
 _RESERVED_CROSSORIGIN_VALUES = frozenset({'anonymous', 'use-credentials'})
 
 _RESERVED_SAMESITE_VALUES = frozenset({'lax', 'strict', 'none'})
@@ -243,18 +238,6 @@ def media(self, value):
         self._media = value
         self._media_rendered = _UNSET
 
-    @property
-    def stream_len(self):
-        # NOTE(kgriffs): Provide some additional information by raising the
-        #   error explicitly.
-        raise AttributeError(_STREAM_LEN_REMOVED_MSG)
-
-    @stream_len.setter
-    def stream_len(self, value):
-        # NOTE(kgriffs): We explicitly disallow setting the deprecated attribute
-        #   so that apps relying on it do not fail silently.
-        raise AttributeError(_STREAM_LEN_REMOVED_MSG)
-
     def render_body(self):
         """Get the raw bytestring content for the response body.
 

tests/test_response.py

@@ -1,3 +1,4 @@
+from io import BytesIO
 from unittest.mock import MagicMock
 
 import pytest
@@ -53,14 +54,6 @@ def test_response_attempt_to_set_read_only_headers(resp):
     assert headers['x-things3'] == 'thing-3a, thing-3b'
 
 
-def test_response_removed_stream_len(resp):
-    with pytest.raises(AttributeError):
-        resp.stream_len = 128
-
-    with pytest.raises(AttributeError):
-        resp.stream_len
-
-
 def test_response_option_mimetype_init(monkeypatch):
     mock = MagicMock()
     mock.inited = False
@@ -81,3 +74,14 @@ def test_response_option_mimetype_init(monkeypatch):
     assert ro.static_media_types['.js'] == 'text/javascript'
     assert ro.static_media_types['.json'] == 'application/json'
     assert ro.static_media_types['.mjs'] == 'text/javascript'
+
+
+@pytest.mark.parametrize('content', [b'', b'dummy content'])
+def test_response_set_stream(resp, content):
+    stream = BytesIO(content)
+    content_length = len(content)
+
+    resp.set_stream(stream, content_length)
+
+    assert resp.stream is stream
+    assert resp.headers['content-length'] == str(content_length)