diff --git a/_test/tests/inc/mailer.test.php b/_test/tests/inc/mailer.test.php
new file mode 100644
index 0000000000000000000000000000000000000000..b2c74a257d24c6667bc9a10be60ad7bb9abac30f
--- /dev/null
+++ b/_test/tests/inc/mailer.test.php
@@ -0,0 +1,94 @@
+<?php
+
+/**
+ * Extends the mailer class to expose internal variables for testing
+ */
+class TestMailer extends Mailer {
+    public function prop($name){
+        return $this->$name;
+    }
+}
+
+class mailer_test extends DokuWikiTest {
+
+
+    function test_userheader(){
+        $mail = new TestMailer();
+        $headers = $mail->prop('headers');
+        $this->assertArrayNotHasKey('X-Dokuwiki-User',$headers);
+
+        $_SERVER['REMOTE_USER'] = 'andi';
+        $mail = new TestMailer();
+        $headers = $mail->prop('headers');
+        $this->assertArrayHasKey('X-Dokuwiki-User',$headers);
+    }
+
+    function test_setHeader(){
+        $mail = new TestMailer();
+
+        // check existance of default headers
+        $headers = $mail->prop('headers');
+        $this->assertArrayHasKey('X-Mailer',$headers);
+        $this->assertArrayHasKey('X-Dokuwiki-Title',$headers);
+        $this->assertArrayHasKey('X-Dokuwiki-Server',$headers);
+        $this->assertArrayHasKey('X-Auto-Response-Suppress',$headers);
+        $this->assertArrayHasKey('List-Id',$headers);
+
+        // set a bunch of test headers
+        $mail->setHeader('test-header','bla');
+        $mail->setHeader('to','A valid ASCII name <test@example.com>');
+        $mail->setHeader('from',"Thös ne\needs\x00serious cleaning$§%.");
+        $mail->setHeader('bad',"Thös ne\needs\x00serious cleaning$§%.",false);
+        $mail->setHeader("weird\n*+\x00foo.-_@bar?",'now clean');
+
+        // are they set?
+        $headers = $mail->prop('headers');
+        $this->assertArrayHasKey('Test-Header',$headers);
+        $this->assertEquals('bla',$headers['Test-Header']);
+        $this->assertArrayHasKey('To',$headers);
+        $this->assertEquals('A valid ASCII name <test@example.com>',$headers['To']);
+        $this->assertArrayHasKey('From',$headers);
+        $this->assertEquals('Ths neeedsserious cleaning.',$headers['From']);
+        $this->assertArrayHasKey('Bad',$headers);
+        $this->assertEquals("Thös ne\needs\x00serious cleaning$§%.",$headers['Bad']);
+        $this->assertArrayHasKey('Weird+foo.-_@bar',$headers);
+
+        // unset a header again
+        $mail->setHeader('test-header','');
+        $headers = $mail->prop('headers');
+        $this->assertArrayNotHasKey('Test-Header',$headers);
+    }
+
+    function test_simplemail(){
+        global $conf;
+        $conf['htmlmail'] = 0;
+        $mail = new TestMailer();
+        $mail->to('test@example.com');
+        $mail->setBody('A test mail in ASCII');
+
+        $dump = $mail->dump();
+        $this->assertNotRegexp('/Content-Type: multipart/',$dump);
+        $this->assertRegexp('#Content-Type: text/plain; charset=UTF-8#',$dump);
+        $this->assertRegexp('/'.base64_encode('A test mail in ASCII').'/',$dump);
+
+        $conf['htmlmail'] = 1;
+    }
+
+    function test_replacements(){
+        $mail = new TestMailer();
+
+        $replacements = array( '@DATE@','@BROWSER@','@IPADDRESS@','@HOSTNAME@',
+                               '@TITLE@','@DOKUWIKIURL@','@USER@','@NAME@','@MAIL@');
+        $mail->setBody('A test mail in with replacements '.join(' ',$replacements));
+
+        $text = $mail->prop('text');
+        $html = $mail->prop('html');
+
+        foreach($replacements as $repl){
+            $this->assertNotRegexp("/$repl/",$text,"$repl replacement still in text");
+            $this->assertNotRegexp("/$repl/",$html,"$repl replacement still in html");
+        }
+    }
+
+}
+//Setup VIM: ex: et ts=4 :