[IMP] doc: add test classes documentation

Closes #13902

doc/reference/testing.rst

@@ -48,6 +48,11 @@ related to testing Odoo content (modules, mainly):
 .. autoclass:: openerp.tests.common.SingleTransactionCase
     :members: browse_ref, ref
 
+.. autoclass:: openerp.tests.common.SavepointCase
+
+.. autoclass:: openerp.tests.common.HttpCase
+    :members: browse_ref, ref, url_open, phantom_js
+
 By default, tests are run once right after the corresponding module has been
 installed. Test cases can also be configured to run after all modules have
 been installed, and not run right after the module installation: