tests: Exercise recent eventlet breakage without XFS

Recently, upper-constraints updated eventlet. Unfortunately, there
was a bug which breaks our unit tests which was not discovered during
the cross-project testing because the affected unit tests require an
XFS temp dir. The requirements change has since been reverted, but we
ought to have tests that cover the problematic behavior that will
actually run as part of cross-project testing.

See https://github.com/eventlet/eventlet/pull/826 for the eventlet
change that introduced the bug; it has since been fixed on master in
https://github.com/eventlet/eventlet/pull/890 (though we still need
https://review.opendev.org/c/openstack/swift/+/905796 to be able to
work with eventlet master).

Change-Id: I4a6d79317b65f746ee29d2d25073b8c3859cd6a0

test/unit/common/test_http_protocol.py

@@ -297,6 +297,28 @@ class TestSwiftHttpProtocolSomeMore(ProtocolTest):
         lines = [l for l in bytes_out.split(b"\r\n") if l]
         self.assertEqual(lines[-1], b'///some-leading-slashes')
 
+    def test_chunked_with_content_length(self):
+        def reflecting_app(env, start_response):
+            start_response('200 OK', [])
+            return [env['wsgi.input'].read()]
+
+        # This is more of a test of eventlet, but we've seen issues with it
+        # before that were only caught in unit tests that require an XFS
+        # tempdir, and so were skipped on the requirements job
+        bytes_out = self._run_bytes_through_protocol((
+            b"PUT /path HTTP/1.0\r\n"
+            b"Content-Length: 10\r\n"
+            b"Transfer-Encoding: chunked\r\n"
+            b"\r\n"
+            b"a\r\n"
+            b"some text\n"
+            b"\r\n"
+            b"0\r\n"
+            b"\r\n"
+        ), app=reflecting_app)
+        body = bytes_out.partition(b"\r\n\r\n")[2]
+        self.assertEqual(body, b'some text\n')
+
     def test_request_lines(self):
         def app(env, start_response):
             start_response("200 OK", [])