def METHOD_NAME(self):
    #################################################
    # lowlevel check for http persistent connection #
    #################################################
    url = urllib.parse.urlparse(self.nodes[0].url)
    authpair = f'{url.username}:{url.password}'
    headers = {"Authorization": f"Basic {str_to_b64str(authpair)}"}
    conn = http.client.HTTPConnection(url.hostname, url.port)
    conn.connect()
    conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1
    assert conn.sock is not None  #according to http/1.1 connection must still be open!
    #send 2nd request without closing connection
    conn.request('POST', '/', '{"method": "getchaintips"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1  #must also response with a correct json-rpc message
    assert conn.sock is not None  #according to http/1.1 connection must still be open!
    conn.close()
    #same should be if we add keep-alive because this should be the std. behaviour
    headers = {"Authorization": f"Basic {str_to_b64str(authpair)}", "Connection": "keep-alive"}
    conn = http.client.HTTPConnection(url.hostname, url.port)
    conn.connect()
    conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1
    assert conn.sock is not None  #according to http/1.1 connection must still be open!
    #send 2nd request without closing connection
    conn.request('POST', '/', '{"method": "getchaintips"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1  #must also response with a correct json-rpc message
    assert conn.sock is not None  #according to http/1.1 connection must still be open!
    conn.close()
    #now do the same with "Connection: close"
    headers = {"Authorization": f"Basic {str_to_b64str(authpair)}", "Connection":"close"}
    conn = http.client.HTTPConnection(url.hostname, url.port)
    conn.connect()
    conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1
    assert conn.sock is None  #now the connection must be closed after the response
    #node1 (2nd node) is running with disabled keep-alive option
    urlNode1 = urllib.parse.urlparse(self.nodes[1].url)
    authpair = f'{urlNode1.username}:{urlNode1.password}'
    headers = {"Authorization": f"Basic {str_to_b64str(authpair)}"}
    conn = http.client.HTTPConnection(urlNode1.hostname, urlNode1.port)
    conn.connect()
    conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1
    #node2 (third node) is running with standard keep-alive parameters which means keep-alive is on
    urlNode2 = urllib.parse.urlparse(self.nodes[2].url)
    authpair = f'{urlNode2.username}:{urlNode2.password}'
    headers = {"Authorization": f"Basic {str_to_b64str(authpair)}"}
    conn = http.client.HTTPConnection(urlNode2.hostname, urlNode2.port)
    conn.connect()
    conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
    out1 = conn.getresponse().read()
    assert b'"error":null' in out1
    assert conn.sock is not None  #connection must be closed because bitcoind should use keep-alive by default
    # Check excessive request size
    conn = http.client.HTTPConnection(urlNode2.hostname, urlNode2.port)
    conn.connect()
    conn.request('GET', f'/{"x"*1000}', '', headers)
    out1 = conn.getresponse()
    assert_equal(out1.status, http.client.NOT_FOUND)
    conn = http.client.HTTPConnection(urlNode2.hostname, urlNode2.port)
    conn.connect()
    conn.request('GET', f'/{"x"*10000}', '', headers)
    out1 = conn.getresponse()
    assert_equal(out1.status, http.client.BAD_REQUEST)