public static boolean hasProxyAddress() {
        return proxyHost != null;
    }
Adaptive ClickHouse server environment for integration test. Two modes are
supported: 1) existing server(when system property {@code clickhouseServer}
is defined); and 2) test container.

<p>
Below system properties can be used for customization:
<ul>
<li>clickhouseServer - host of clickhouse server</li>
<li>clickhouse&lt;Protocol&gt;Port - port of specific protocol, for example:
{@code clickhouseGRPCPort}</li>
<li>clickhouseImage - custom docker image, with or without tag and/or image
digest</li>
<li>clickhouseVersion - version of clickhouse, could be replaced by the one
used in {@code clickhouseImage}</li>
<li>clickhouseTimezone - server timezone</li>
<li>additionalPackages - additional system packages should be installed in
container mode</li>
</ul>
clickhouse-client/src/test/java/com/clickhouse/client/ClickHouseServerForTest.java