Add TestCase for feature/ISSUE-5436

dbms/tests/integration/test_custom_http/configs/custom_http.xml

+<yandex>
+    <http_port>8123</http_port>
+    <CustomHTTP>
+        <HTTPMatch>
+            <URL>/${database}/a/${id}/${table}</URL>
+            <QUERY>INSERT INTO ${database:ASTIdentifier}.${table:ASTIdentifier}(id) VALUES</QUERY>
+            <QUERY>SELECT * FROM ${database:ASTIdenfier}.t</QUERY>
+            <QUERY>SELECT * FROM a.${table:ASTIdenfier} WHERE id={id:UInt8}</QUERY>
+        </HTTPMatch>
+    </CustomHTTP>
+</yandex>

dbms/tests/integration/test_custom_http/test.py

+import pytest
+import requests
+
+from helpers.cluster import ClickHouseCluster
+from helpers.test_tools import assert_eq_with_retry
+
+cluster = ClickHouseCluster(__file__)
+node = cluster.add_instance('node', main_configs=['configs/custom_http.xml'])
+
+@pytest.fixture(scope="module")
+def start_cluster():
+    try:
+        cluster.start()
+        node.query('''
+CREATE DATABASE `test`;
+
+CREATE TABLE `test`.`test_custom_http` (`id` UInt8) Engine=Memory;
+        ''')
+
+        yield cluster
+    finally:
+        cluster.shutdown()
+
+def test(started_cluster):
+    node_ip = cluster.get_instance_ip(node)
+    url = 'http://%s:8123/test/a/1/test_custom_http' % node_ip
+    data="(1)"
+    params = {'id':1}
+    response = requests.post(url, params = params, data = data)
+
+    assert response.text == '\n1\n1\n'