test responses fail with incomplete body reads

tests/test_lowlevel.py

@@ -24,6 +24,23 @@ def test_chunked_upload():
     assert r.status_code == 200
     assert r.request.headers['Transfer-Encoding'] == 'chunked'
 
+def test_incorrect_content_length():
+    """Test ConnectionError raised for incomplete responses"""
+    close_server = threading.Event()
+    server = Server.text_response_server(
+            "HTTP/1.1 200 OK\r\n" +
+            "Content-Length: 50\r\n\r\n" +
+            "Hello World."
+        )
+    with server as (host, port):
+        url = 'http://{0}:{1}/'.format(host, port)
+        r = requests.Request('GET', url).prepare()
+        s = requests.Session()
+        with pytest.raises(requests.exceptions.ConnectionError) as e:
+            resp = s.send(r)
+        assert "12 bytes read, 38 more expected" in str(e)
+        close_server.set()  # release server block
+
 
 _schemes_by_var_prefix = [
     ('http', ['http']),