diff --git a/mod/workshop/locallib.php b/mod/workshop/locallib.php
index 824ccdc251f..9c89c718eee 100644
--- a/mod/workshop/locallib.php
+++ b/mod/workshop/locallib.php
@@ -424,11 +424,15 @@ class workshop {
      * Empty values are not returned. Values are converted to lowercase.
      * Duplicates are removed. Glob evaluation is not supported.
      *
+     * @deprecated since Moodle 3.4 MDL-56486 - please use the {@link core_form\filetypes_util}
      * @param string|array $extensions list of file extensions
      * @return array of strings
      */
     public static function normalize_file_extensions($extensions) {
 
+        debugging('The method workshop::normalize_file_extensions() is deprecated.
+            Please use the methods provided by the \core_form\filetypes_util class.', DEBUG_DEVELOPER);
+
         if ($extensions === '') {
             return array();
         }
@@ -464,11 +468,15 @@ class workshop {
     /**
      * Cleans the user provided list of file extensions.
      *
+     * @deprecated since Moodle 3.4 MDL-56486 - please use the {@link core_form\filetypes_util}
      * @param string $extensions
      * @return string
      */
     public static function clean_file_extensions($extensions) {
 
+        debugging('The method workshop::clean_file_extensions() is deprecated.
+            Please use the methods provided by the \core_form\filetypes_util class.', DEBUG_DEVELOPER);
+
         $extensions = self::normalize_file_extensions($extensions);
 
         foreach ($extensions as $i => $extension) {
@@ -483,12 +491,16 @@ class workshop {
      *
      * Empty whitelist is interpretted as "any extension is valid".
      *
+     * @deprecated since Moodle 3.4 MDL-56486 - please use the {@link core_form\filetypes_util}
      * @param string|array $extensions list of file extensions
      * @param string|array $whitelist list of valid extensions
      * @return array list of invalid extensions not found in the whitelist
      */
     public static function invalid_file_extensions($extensions, $whitelist) {
 
+        debugging('The method workshop::invalid_file_extensions() is deprecated.
+            Please use the methods provided by the \core_form\filetypes_util class.', DEBUG_DEVELOPER);
+
         $extensions = self::normalize_file_extensions($extensions);
         $whitelist = self::normalize_file_extensions($whitelist);
 
@@ -506,12 +518,16 @@ class workshop {
      * Empty whitelist is interpretted as "any file type is allowed" rather
      * than "no file can be uploaded".
      *
+     * @deprecated since Moodle 3.4 MDL-56486 - please use the {@link core_form\filetypes_util}
      * @param string $filename the file name
      * @param string|array $whitelist list of allowed file extensions
      * @return false
      */
     public static function is_allowed_file_type($filename, $whitelist) {
 
+        debugging('The method workshop::is_allowed_file_type() is deprecated.
+            Please use the methods provided by the \core_form\filetypes_util class.', DEBUG_DEVELOPER);
+
         $whitelist = self::normalize_file_extensions($whitelist);
 
         if (empty($whitelist)) {
diff --git a/mod/workshop/tests/locallib_test.php b/mod/workshop/tests/locallib_test.php
index 2133e0af0ee..a81ea0f8b1f 100644
--- a/mod/workshop/tests/locallib_test.php
+++ b/mod/workshop/tests/locallib_test.php
@@ -636,26 +636,8 @@ class mod_workshop_internal_api_testcase extends advanced_testcase {
     public function test_normalize_file_extensions() {
         $this->resetAfterTest(true);
 
-        $this->assertSame(['.odt'], workshop::normalize_file_extensions('odt'));
-        $this->assertSame(['.odt'], workshop::normalize_file_extensions('.odt'));
-        $this->assertSame(['.odt'], workshop::normalize_file_extensions('.ODT'));
-        $this->assertSame(['.doc', '.jpg', '.mp3'], workshop::normalize_file_extensions('doc, jpg, mp3'));
-        $this->assertSame(['.doc', '.jpg', '.mp3'], workshop::normalize_file_extensions(['.doc', '.jpg', '.mp3']));
-        $this->assertSame(['.doc', '.jpg', '.mp3'], workshop::normalize_file_extensions('doc, *.jpg, mp3'));
-        $this->assertSame(['.doc', '.jpg', '.mp3'], workshop::normalize_file_extensions(['doc ', ' JPG ', '.mp3']));
-        $this->assertSame(['.rtf', '.pdf', '.docx'], workshop::normalize_file_extensions("RTF,.pdf\n...DocX,,,;\rPDF\trtf ...Rtf"));
-        $this->assertSame(['.tgz', '.tar.gz'], workshop::normalize_file_extensions('tgz,TAR.GZ tar.gz .tar.gz tgz TGZ'));
-        $this->assertSame(['.notebook'], workshop::normalize_file_extensions('"Notebook":notebook;NOTEBOOK;,\'NoTeBook\''));
-        $this->assertSame([], workshop::normalize_file_extensions(''));
-        $this->assertSame([], workshop::normalize_file_extensions([]));
-        $this->assertSame(['.0'], workshop::normalize_file_extensions(0));
-        $this->assertSame(['.0'], workshop::normalize_file_extensions('0'));
-        $this->assertSame(['.odt'], workshop::normalize_file_extensions('*.odt'));
-        $this->assertSame([], workshop::normalize_file_extensions('.'));
-        $this->assertSame(['.foo'], workshop::normalize_file_extensions('. foo'));
-        $this->assertSame([], workshop::normalize_file_extensions('*'));
-        $this->assertSame([], workshop::normalize_file_extensions('*~'));
-        $this->assertSame(['.pdf', '.ps'], workshop::normalize_file_extensions('* pdf *.ps foo* *bar .r??'));
+        workshop::normalize_file_extensions('');
+        $this->assertDebuggingCalled();
     }
 
     /**
@@ -664,13 +646,8 @@ class mod_workshop_internal_api_testcase extends advanced_testcase {
     public function test_clean_file_extensions() {
         $this->resetAfterTest(true);
 
-        $this->assertSame('', workshop::clean_file_extensions(''));
-        $this->assertSame('', workshop::clean_file_extensions(null));
-        $this->assertSame('', workshop::clean_file_extensions(' '));
-        $this->assertSame('0', workshop::clean_file_extensions(0));
-        $this->assertSame('0', workshop::clean_file_extensions('0'));
-        $this->assertSame('doc, rtf, pdf', workshop::clean_file_extensions('*.Doc, RTF, PDF, .rtf'.PHP_EOL.'PDF '));
-        $this->assertSame('doc, rtf, pdf', 'doc, rtf, pdf');
+        workshop::clean_file_extensions('');
+        $this->assertDebuggingCalledCount(2);
     }
 
     /**
@@ -679,20 +656,8 @@ class mod_workshop_internal_api_testcase extends advanced_testcase {
     public function test_invalid_file_extensions() {
         $this->resetAfterTest(true);
 
-        $this->assertSame([], workshop::invalid_file_extensions('', ''));
-        $this->assertSame([], workshop::invalid_file_extensions('', '.doc'));
-        $this->assertSame([], workshop::invalid_file_extensions('odt', ''));
-        $this->assertSame([], workshop::invalid_file_extensions('odt', '*'));
-        $this->assertSame([], workshop::invalid_file_extensions('odt', 'odt'));
-        $this->assertSame([], workshop::invalid_file_extensions('doc, odt, pdf', ['pdf', 'doc', 'odt']));
-        $this->assertSame([], workshop::invalid_file_extensions(['doc', 'odt', 'PDF'], ['.doc', '.pdf', '.odt']));
-        $this->assertSame([], workshop::invalid_file_extensions('*~ .docx, Odt PDF :doc .pdf', '*.docx *.odt *.pdf *.doc'));
-        $this->assertSame(['.00001-wtf-is-this'], workshop::invalid_file_extensions('docx tgz .00001-wtf-is-this', 'tgz docx'));
-        $this->assertSame(['.foobar', '.wtfisthis'], workshop::invalid_file_extensions(['.pdf', '.foobar', 'wtfisthis'], 'pdf'));
-        $this->assertSame([], workshop::invalid_file_extensions('', ''));
-        $this->assertSame(['.odt'], workshop::invalid_file_extensions(['.PDF', 'PDF', '.ODT'], 'jpg pdf png gif'));
-        $this->assertSame(['.odt'], workshop::invalid_file_extensions(['.PDF', 'PDF', '.ODT'], '.jpg,.pdf,  .png .gif'));
-        $this->assertSame(['.exe', '.bat'], workshop::invalid_file_extensions(['.exe', '.odt', '.bat', ''], 'odt'));
+        workshop::invalid_file_extensions('', '');
+        $this->assertDebuggingCalledCount(3);
     }
 
     /**
@@ -701,29 +666,8 @@ class mod_workshop_internal_api_testcase extends advanced_testcase {
     public function test_is_allowed_file_type() {
         $this->resetAfterTest(true);
 
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', ''));
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', ['']));
-        $this->assertFalse(workshop::is_allowed_file_type('README.txt', '0'));
-
-        $this->assertFalse(workshop::is_allowed_file_type('README.txt', 'xt'));
-        $this->assertFalse(workshop::is_allowed_file_type('README.txt', 'old.txt'));
-
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', 'txt'));
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', '.TXT'));
-        $this->assertTrue(workshop::is_allowed_file_type('README.TXT', 'txt'));
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', '.txt .md'));
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', 'HTML TXT DOC RTF'));
-        $this->assertTrue(workshop::is_allowed_file_type('README.txt', ['HTML', '...TXT', 'DOC', 'RTF']));
-
-        $this->assertTrue(workshop::is_allowed_file_type('C:\Moodle\course-data.tar.gz', 'gzip zip 7z tar.gz'));
-        $this->assertFalse(workshop::is_allowed_file_type('C:\Moodle\course-data.tar.gz', 'gzip zip 7z tar'));
-        $this->assertTrue(workshop::is_allowed_file_type('~/course-data.tar.gz', 'gzip zip 7z gz'));
-        $this->assertFalse(workshop::is_allowed_file_type('~/course-data.tar.gz', 'gzip zip 7z'));
-
-        $this->assertFalse(workshop::is_allowed_file_type('Alice on the beach.jpg.exe', 'png gif jpg bmp'));
-        $this->assertFalse(workshop::is_allowed_file_type('xfiles.exe.jpg', 'exe com bat sh'));
-        $this->assertFalse(workshop::is_allowed_file_type('solution.odt~', 'odt, xls'));
-        $this->assertTrue(workshop::is_allowed_file_type('solution.odt~', 'odt, odt~'));
+        workshop::is_allowed_file_type('', '');
+        $this->assertDebuggingCalledCount(2);
     }
 
     /**