diff --git a/changelog.d/17545.bugfix b/changelog.d/17545.bugfix
index 9e9e10f3cba..31e22d873e9 100644
--- a/changelog.d/17545.bugfix
+++ b/changelog.d/17545.bugfix
@@ -1 +1 @@
-Handle lower-case http headers in _Mulitpart_Parser_Protocol.
\ No newline at end of file
+Handle lower-case http headers in `_Mulitpart_Parser_Protocol`.
\ No newline at end of file
diff --git a/tests/http/test_client.py b/tests/http/test_client.py
index 6447635f817..f2abec190bd 100644
--- a/tests/http/test_client.py
+++ b/tests/http/test_client.py
@@ -49,9 +49,11 @@
 
 
 class ReadMultipartResponseTests(TestCase):
-    data1 = b"\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-Type: application/json\r\n\r\n{}\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-Type: text/plain\r\nContent-Disposition: inline; filename=test_upload\r\n\r\nfile_"
-    data2 = b"to_stream\r\n--6067d4698f8d40a0a794ea7d7379d53a--\r\n\r\n"
-    data3 = b"\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\ncontent-type: application/json\r\n\r\n{}\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\ncontent-type: text/plain\r\ncontent-disposition: inline; filename=test_upload\r\n\r\nfile_"
+    multipart_response_data1 = b"\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-Type: application/json\r\n\r\n{}\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-Type: text/plain\r\nContent-Disposition: inline; filename=test_upload\r\n\r\nfile_"
+    multipart_response_data2 = (
+        b"to_stream\r\n--6067d4698f8d40a0a794ea7d7379d53a--\r\n\r\n"
+    )
+    multipart_response_data_cased = b"\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\ncOntEnt-type: application/json\r\n\r\n{}\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-tyPe: text/plain\r\nconTent-dispOsition: inline; filename=test_upload\r\n\r\nfile_"
 
     redirect_data = b"\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nContent-Type: application/json\r\n\r\n{}\r\n--6067d4698f8d40a0a794ea7d7379d53a\r\nLocation: https://cdn.example.org/ab/c1/2345.txt\r\n\r\n--6067d4698f8d40a0a794ea7d7379d53a--\r\n\r\n"
 
@@ -104,8 +106,8 @@ def test_parse_file(self) -> None:
         result, deferred, protocol = self._build_multipart_response(249, 250)
 
         # Start sending data.
-        protocol.dataReceived(self.data1)
-        protocol.dataReceived(self.data2)
+        protocol.dataReceived(self.multipart_response_data1)
+        protocol.dataReceived(self.multipart_response_data2)
         # Close the connection.
         protocol.connectionLost(Failure(ResponseDone()))
 
@@ -127,8 +129,8 @@ def test_parse_file_lowercase_headers(self) -> None:
         result, deferred, protocol = self._build_multipart_response(249, 250)
 
         # Start sending data.
-        protocol.dataReceived(self.data3)
-        protocol.dataReceived(self.data2)
+        protocol.dataReceived(self.multipart_response_data_cased)
+        protocol.dataReceived(self.multipart_response_data2)
         # Close the connection.
         protocol.connectionLost(Failure(ResponseDone()))
 
@@ -167,7 +169,7 @@ def test_too_large(self) -> None:
         result, deferred, protocol = self._build_multipart_response(UNKNOWN_LENGTH, 180)
 
         # Start sending data.
-        protocol.dataReceived(self.data1)
+        protocol.dataReceived(self.multipart_response_data1)
 
         self.assertEqual(result.getvalue(), b"file_")
         self._assert_error(deferred, protocol)
@@ -178,11 +180,11 @@ def test_additional_data(self) -> None:
         result, deferred, protocol = self._build_multipart_response(UNKNOWN_LENGTH, 180)
 
         # Start sending data.
-        protocol.dataReceived(self.data1)
+        protocol.dataReceived(self.multipart_response_data1)
         self._assert_error(deferred, protocol)
 
         # More data might have come in.
-        protocol.dataReceived(self.data2)
+        protocol.dataReceived(self.multipart_response_data2)
 
         self.assertEqual(result.getvalue(), b"file_")
         self._assert_error(deferred, protocol)
@@ -196,7 +198,7 @@ def test_content_length(self) -> None:
         self.assertFalse(deferred.called)
 
         # Start sending data.
-        protocol.dataReceived(self.data1)
+        protocol.dataReceived(self.multipart_response_data1)
         self._assert_error(deferred, protocol)
         self._cleanup_error(deferred)