Throw exception if message does not exist

src/Exception/MessageDoesNotExistException.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Ddeboer\Imap\Exception;
+
+class MessageDoesNotExistException extends Exception
+{
+    public function __construct($number, $error)
+    {
+        parent::__construct(
+            sprintf(
+                'Message %s does not exist: %s',
+                $number,
+                $error
+            )
+        );
+    }
+}

src/Message.php

@@ -2,6 +2,7 @@
 
 namespace Ddeboer\Imap;
 
+use Ddeboer\Imap\Exception\MessageDoesNotExistException;
 use Ddeboer\Imap\Message\EmailAddress;
 use Ddeboer\Imap\Exception\MessageDeleteException;
 use Ddeboer\Imap\Exception\MessageMoveException;
@@ -307,7 +308,23 @@ public function keepUnseen($bool = true)
      */
     private function loadStructure()
     {
-        $structure = imap_fetchstructure($this->stream, $this->messageNumber, \FT_UID);
+        set_error_handler(
+            function ($nr, $error) {
+                throw new MessageDoesNotExistException(
+                    $this->messageNumber,
+                    $error
+                );
+            }
+        );
+
+        $structure = imap_fetchstructure(
+            $this->stream,
+            $this->messageNumber,
+            \FT_UID
+        );
+
+        restore_error_handler();
+
         $this->parseStructure($structure);
     }
 }

tests/MailboxTest.php

@@ -43,6 +43,15 @@ public function testGetMessages()
         $this->assertEquals(3, $i);
     }
 
+    /**
+     * @expectedException \Ddeboer\Imap\Exception\MessageDoesNotExistException
+     * @expectedExceptionMessageRegExp /Message 666 does not exist.*Bad message number/
+     */
+    public function testGetMessageThrowsException()
+    {
+        $this->mailbox->getMessage(666);
+    }
+
     public function testCount()
     {
         $this->assertEquals(3, $this->mailbox->count());