diff --git a/lib/simpletest/testmoodlelib.php b/lib/simpletest/testmoodlelib.php
index 3a2bd3e001d..0142a665aa0 100644
--- a/lib/simpletest/testmoodlelib.php
+++ b/lib/simpletest/testmoodlelib.php
@@ -961,12 +961,23 @@ class moodlelib_test extends UnitTestCase {
         $this->assertEqual($text, shorten_text($text)); // 30 chars by default
         $this->assertEqual("Žluťoučký koníče...", shorten_text($text, 19, true));
         $this->assertEqual("Žluťoučký ...", shorten_text($text, 19, false));
+        // And try it with 2-less (that are, in bytes, the middle of a sequence)
+        $this->assertEqual("Žluťoučký koní...", shorten_text($text, 17, true));
+        $this->assertEqual("Žluťoučký ...", shorten_text($text, 17, false));
 
         $text = "<p>Žluťoučký koníček <b>přeskočil</b> potůček</p>";
         $this->assertEqual($text, shorten_text($text, 60));
         $this->assertEqual("<p>Žluťoučký koníček ...</p>", shorten_text($text, 21));
         $this->assertEqual("<p>Žluťoučký koníče...</p>", shorten_text($text, 19, true));
         $this->assertEqual("<p>Žluťoučký ...</p>", shorten_text($text, 19, false));
+        // And try it with 2-less (that are, in bytes, the middle of a sequence)
+        $this->assertEqual("<p>Žluťoučký koní...</p>", shorten_text($text, 17, true));
+        $this->assertEqual("<p>Žluťoučký ...</p>", shorten_text($text, 17, false));
+        // And try over one tag (start/end), it does proper text len
+        $this->assertEqual("<p>Žluťoučký koníček <b>př...</b></p>", shorten_text($text, 23, true));
+        $this->assertEqual("<p>Žluťoučký koníček <b>přeskočil</b> pot...</p>", shorten_text($text, 34, true));
+        // And in the middle of one tag
+        $this->assertEqual("<p>Žluťoučký koníček <b>přeskočil...</b></p>", shorten_text($text, 30, true));
 
         // Japanese
         $text = '言語設定言語設定abcdefghijkl';
@@ -1784,4 +1795,4 @@ class moodlelib_test extends UnitTestCase {
         // Reset the language
         $COURSE->lang = $originallang;
     }
-}
\ No newline at end of file
+}