Add tests and fix issue with array_merge

src/Monolog/ErrorHandler.php

@@ -78,7 +78,12 @@ class ErrorHandler
     public function registerErrorHandler(array $levelMap = array(), $callPrevious = true, $errorTypes = -1)
     {
         $prev = set_error_handler(array($this, 'handleError'), $errorTypes);
-        $this->errorLevelMap = array_merge($this->defaultErrorLevelMap(), $levelMap);
+        $this->errorLevelMap = $this->defaultErrorLevelMap();
+        // merging the map into the defaults by hand because array_merge
+        // trips up on numeric keys
+        foreach ($levelMap as $key => $val) {
+            $this->errorLevelMap[$key] = $val;
+        }
         if ($callPrevious) {
             $this->previousErrorHandler = $prev ?: true;
         }

tests/Monolog/ErrorHandlerTest.php

@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the Monolog package.
+ *
+ * (c) Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Monolog;
+
+use Monolog\Handler\TestHandler;
+
+class ErrorHandlerTest extends \PHPUnit_Framework_TestCase
+{
+    public function testHandleError()
+    {
+        $logger = new Logger('test', array($handler = new TestHandler));
+        $errHandler = new ErrorHandler($logger);
+
+        $errHandler->registerErrorHandler(array(E_USER_NOTICE => Logger::EMERGENCY), false);
+        trigger_error('Foo', E_USER_ERROR);
+        $this->assertCount(1, $handler->getRecords());
+        $this->assertTrue($handler->hasErrorRecords());
+        trigger_error('Foo', E_USER_NOTICE);
+        $this->assertCount(2, $handler->getRecords());
+        $this->assertTrue($handler->hasEmergencyRecords());
+    }
+}