Add a wiki to your Moodle. Open the following URL and check that the error " Invalid parameters have been given " is shown. YOURMOODLE/mod/wiki/view.php Now open the following URL using an invalid pageid and check that the error " Page ID is incorrect " is shown. YOURMOODLE/mod/wiki/view.php?pageid=999 Unfortunately, the other errors cannot be reproduced without manually modifying the database. Add a page to your wiki. Go to the table mdl_wiki_pages in the database, search for the page you just created and modify its subwikiid . Use a subwikiid that doesn't exist. Open the following URL using your pageid and check that the error " Subwiki ID is incorrect " is shown. YOURMOODLE/mod/wiki/view.php?pageid=1 Go back to the DB and leave the subwikiid value like it was. Now go to the table mdl_wiki_subwikis , search the subwiki your page belongs to and change its wikiid . Use a wikiid that doesn't exist. Open the following URL using your pageid and check that the error " Wiki ID is incorrect " is shown. YOURMOODLE/mod/wiki/view.php?pageid=1 Now open the following URL using the subwiki ID that you have changed. Check that the error " Wiki ID is incorrect " is shown. YOURMOODLE/mod/wiki/create.php?swid=1 Go back to the DB and leave the wikiid value like it was. Open the following URL using a valid pageid . Check that the error "A page version can only be compared with an older version." is shown. YOURMOODLE/mod/wiki/diff.php?pageid=1&comparewith=1&compare=2