Test that dnsmasq.addnhosts with ipv6_enabled produces both
127.0.0.1 and :: entries (dual-stack).

-- Testcase --
import adb from 'adblock-fast';
import { readfile } from 'fs';
let ti = adb._test_internals;

adb.env.load_config();
ti.set_cfg('dns', 'dnsmasq.addnhosts');
ti.set_cfg('ipv6_enabled', true);
ti.set_cfg('dnsmasq_sanity_check', false);
ti.set_cfg('dnsmasq_validity_check', false);
ti.set_cfg('heartbeat_domain', null);
ti.set_cfg('config_update_enabled', false);
ti.set_cfg('update_config_sizes', false);
ti.env.dns_set_output_values('dnsmasq.addnhosts');
ti.append_urls();

let ok = ti.download_lists();
if (!ok) {
	print('download_lists failed\n');
} else {
	let content = readfile(ti.dns_output.file) || '';
	let lines = filter(split(content, '\n'), l => length(l) > 0);

	let ipv4_lines = filter(lines, l => match(l, /^127\.0\.0\.1 /));
	let ipv6_lines = filter(lines, l => match(l, /^:: /));

	let results = [];
	push(results, sprintf('ipv4_count: %d', length(ipv4_lines)));
	push(results, sprintf('ipv6_count: %d', length(ipv6_lines)));
	push(results, sprintf('counts_match: %s', length(ipv4_lines) == length(ipv6_lines) ? 'YES' : 'NO'));

	// Spot-check a specific domain appears in both
	let test_domain = 'ad.doubleclick.test.example.com';
	let has_ipv4 = index(content, '127.0.0.1 ' + test_domain) >= 0;
	let has_ipv6 = index(content, ':: ' + test_domain) >= 0;
	push(results, sprintf('dual_stack_%s: %s', test_domain, (has_ipv4 && has_ipv6) ? 'YES' : 'NO'));

	print(join('\n', results) + '\n');
}
-- End --

-- Expect stdout --
ipv4_count: 165
ipv6_count: 165
counts_match: YES
dual_stack_ad.doubleclick.test.example.com: YES
-- End --