Pass random function to allow mocking

[MAILPOET-2321]

lib/Logging/LogHandler.php

@@ -19,6 +19,20 @@ class LogHandler extends AbstractProcessingHandler {
    */
   const DAYS_TO_KEEP_LOGS = 30;
 
+  /** @var callable */
+  private $rand_function;
+
+  public function __construct($level = \MailPoetVendor\Monolog\Logger::DEBUG, $bubble = \true, $rand_function = null) {
+    parent::__construct($level, $bubble);
+    if (!$rand_function) {
+      $this->rand_function = function($min, $max) {
+        return rand($min, $max);
+      };
+    } else {
+      $this->rand_function = $rand_function;
+    }
+  }
+
   protected function write(array $record) {
     $model = $this->createNewLogModel();
     $model->hydrate([
@@ -39,7 +53,7 @@ class LogHandler extends AbstractProcessingHandler {
   }
 
   private function getRandom() {
-    return rand(0, 100);
+    return call_user_func($this->rand_function, 0, 100);
   }
 
   private function purgeOldLogs() {

tests/integration/Logging/LogHandlerTest.php

@@ -43,9 +43,11 @@ class LogHandlerTest extends \MailPoetTest {
       'created_at' => Carbon::create()->subDays(100)->toDateTimeString(),
     ]);
     $model->save();
+    $random = function() {
+      return 0;
+    };
 
-    $log_handler = new LogHandler();
+    $log_handler = new LogHandler(\MailPoetVendor\Monolog\Logger::DEBUG, true, $random);
-    $log_handler = Mock::double($log_handler, ['getRandom' => 0]);
     $log_handler->handle([
       'level' => \MailPoetVendor\Monolog\Logger::EMERGENCY,
       'extra' => [],
@@ -67,9 +69,11 @@ class LogHandlerTest extends \MailPoetTest {
       'created_at' => Carbon::create()->subDays(100)->toDateTimeString(),
     ]);
     $model->save();
+    $random = function() {
+      return 100;
+    };
 
-    $log_handler = new LogHandler();
+    $log_handler = new LogHandler(\MailPoetVendor\Monolog\Logger::DEBUG, true, $random);
-    $log_handler = Mock::double($log_handler, ['getRandom' => 100]);
     $log_handler->handle([
       'level' => \MailPoetVendor\Monolog\Logger::EMERGENCY,
       'extra' => [],