Mocking Symfony Ldap::create for unit tests - php

Question

Recently I have been working on an LDAP authentication provider for MediaWiki. In my mind, I have been trying to tackle this issue for a number of days now and cannot come up with a solution.
Context
The way I have developed this plugin is to allow configuration of a number of servers to which we will connect. If we cannot connect to one server, we will try the next... And so on until all are exhausted.
To facilitate this, I have a function in my class that loops over the servers attempting a connection until one succeeds:
private function connect( LdapAuthenticationRequest $req ) {
$dn = $this->config->get( 'BindDN' )[$req->domain];
$pass = $this->config->get( 'BindPass' )[$req->domain];
$servers = $this->config->get( 'Servers' )[$req->domain];
$encryption = $this->config->get( 'EncryptionType' )[$req->domain];
if ( false === $dn ) {
$msgkey = 'ldapauth-attempt-bind-search';
$bind_with = [ null, null ];
} else {
$msgkey = 'ldapauth-attempt-bind-dn-search';
$bind_with = [ $dn, $pass ];
}
$message = new Message( $msgkey, [
'dn' => "{$dn}#{$req->domain}",
] );
$this->logger->info( $message->text() );
foreach ( $servers as $server ) {
if ( false === $server ) {
continue;
}
$ldap = Ldap::create( 'ext_ldap', [
'host' => $server,
'encryption' => $encryption
] );
// Attempt bind - on failure, throw an exception
try {
call_user_func_array( [ $ldap, 'bind' ], $bind_with );
$this->server = $server;
$this->encryption = $encryption;
// log successful bind
$msgkey = 'ldapauth-bind-success';
$message = wfMessage( $msgkey )->text();
$this->logger->info( $message );
return $ldap;
} catch ( SymException $e ) {
if ( false === $dn ) {
$msgkey = 'ldapauth-no-bind-search';
} else {
$msgkey = 'ldapauth-no-bind-dn-search';
}
$message = new Message( $msgkey, [
'dn' => "{$dn}#{$req->domain}",
] );
$message = $message->text();
$this->logger->info( $message );
$this->logger->debug( $e->getMessage() );
}
}
I have been trying to come up with a better way to do this, one that would permit me to better unit-test this class, but thus far I am drawing blanks.
A big part of the reason that I am stuck on this issue is that Symfony's LDAP adapter is essentially hard-coupled into my code, as the call to connect is a static call into Symfony's codebase. i.e. I cannot pass in a connector instance of some description that would then attempt the connection. Do I simply wrap Ldap::create with my own connection wrapper, perhaps?

Answer 1

Since you are using Symfony, I guess your best bet would be to inject LDap object using the framework's dependency injection. However I am not an expert in Symfony. So as a simple hack, I would do it like this :
private function connect($req)
{
$dn = $this->config->get('BindDN')[$req->domain];
$pass = $this->config->get('BindPass')[$req->domain];
$servers = $this->config->get('Servers')[$req->domain];
$encryption = $this->config->get('EncryptionType')[$req->domain];
if (false === $dn) {
$msgkey = 'ldapauth-attempt-bind-search';
$bind_with = [null, null];
} else {
$msgkey = 'ldapauth-attempt-bind-dn-search';
$bind_with = [$dn, $pass];
}
$message = new Message($msgkey, [
'dn' => "{$dn}#{$req->domain}",
]);
$this->logger->info($message->text());
foreach ($servers as $server) {
if (false === $server) {
continue;
}
$ldap = $this->createLDAPObject($server, $encryption);
// Attempt bind - on failure, throw an exception
try {
call_user_func_array([$ldap, 'bind'], $bind_with);
$this->server = $server;
$this->encryption = $encryption;
// log successful bind
$msgkey = 'ldapauth-bind-success';
$message = wfMessage($msgkey)->text();
$this->logger->info($message);
return $ldap;
} catch (SymException $e) {
if (false === $dn) {
$msgkey = 'ldapauth-no-bind-search';
} else {
$msgkey = 'ldapauth-no-bind-dn-search';
}
$message = new Message($msgkey, [
'dn' => "{$dn}#{$req->domain}",
]);
$message = $message->text();
$this->logger->info($message);
$this->logger->debug($e->getMessage());
}
}
}
/**
* #param $server
* #param $encryption
* #return mixed
*/
public function createLDAPObject($server, $encryption)
{
return Ldap::create('ext_ldap', [
'host' => $server,
'encryption' => $encryption
]);
}
Then, you can mock the member method createLDAPObject instead of mocking the static method Ldap::create, which should be easier.
However, I would recommend that you refactor your code, so that it is more readable and testable.
1- First of all, call_user_func_array() is not really test-friendly, and I think your requirements here are not too dynamic so you can replace that line with $ldap->bind($bind_with[0],$bind_with[1]);
2- Your connect method is too large to be tested. Please read about Code Smells - Long Methods
3- The method can be refactored into smaller version by decoupling the presentation from the logic. Like for example you are getting the Message object to get the text from the $msgkey just to log it, which is not helping in code readability and test-ability.
These are my first thoughts on the thing :)
Happy coding & testing :)