new file mode 100644
--- /dev/null
+++ b/examples/trac/trac/ticket/tests/api.py
@@ -0,0 +1,109 @@
+from trac.config import Configuration
+from trac.ticket.api import TicketSystem
+from trac.test import EnvironmentStub, Mock
+
+import unittest
+
+
+class TicketSystemTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.env = EnvironmentStub()
+        self.ticket_system = TicketSystem(self.env)
+
+    def test_custom_field_text(self):
+        self.env.config.set('ticket-custom', 'test', 'text')
+        self.env.config.set('ticket-custom', 'test.label', 'Test')
+        self.env.config.set('ticket-custom', 'test.value', 'Foo bar')
+        fields = TicketSystem(self.env).get_custom_fields()
+        self.assertEqual({'name': 'test', 'type': 'text', 'label': 'Test',
+                          'value': 'Foo bar', 'order': 0},
+                         fields[0])
+
+    def test_custom_field_select(self):
+        self.env.config.set('ticket-custom', 'test', 'select')
+        self.env.config.set('ticket-custom', 'test.label', 'Test')
+        self.env.config.set('ticket-custom', 'test.value', '1')
+        self.env.config.set('ticket-custom', 'test.options', 'option1|option2')
+        fields = TicketSystem(self.env).get_custom_fields()
+        self.assertEqual({'name': 'test', 'type': 'select', 'label': 'Test',
+                          'value': '1', 'options': ['option1', 'option2'],
+                          'order': 0},
+                         fields[0])
+
+    def test_custom_field_textarea(self):
+        self.env.config.set('ticket-custom', 'test', 'textarea')
+        self.env.config.set('ticket-custom', 'test.label', 'Test')
+        self.env.config.set('ticket-custom', 'test.value', 'Foo bar')
+        self.env.config.set('ticket-custom', 'test.cols', '60')
+        self.env.config.set('ticket-custom', 'test.rows', '4')
+        fields = TicketSystem(self.env).get_custom_fields()
+        self.assertEqual({'name': 'test', 'type': 'textarea', 'label': 'Test',
+                          'value': 'Foo bar', 'width': 60, 'height': 4,
+                          'order': 0},
+                         fields[0])
+
+    def test_custom_field_order(self):
+        self.env.config.set('ticket-custom', 'test1', 'text')
+        self.env.config.set('ticket-custom', 'test1.order', '2')
+        self.env.config.set('ticket-custom', 'test2', 'text')
+        self.env.config.set('ticket-custom', 'test2.order', '1')
+        fields = TicketSystem(self.env).get_custom_fields()
+        self.assertEqual('test2', fields[0]['name'])
+        self.assertEqual('test1', fields[1]['name'])
+
+    def test_available_actions_full_perms(self):
+        ts = TicketSystem(self.env)
+        perm = Mock(has_permission=lambda x: 1)
+        self.assertEqual(['leave', 'resolve', 'reassign', 'accept'],
+                         ts.get_available_actions({'status': 'new'}, perm))
+        self.assertEqual(['leave', 'resolve', 'reassign'],
+                         ts.get_available_actions({'status': 'assigned'}, perm))
+        self.assertEqual(['leave', 'resolve', 'reassign'],
+                         ts.get_available_actions({'status': 'reopened'}, perm))
+        self.assertEqual(['leave', 'reopen'],
+                         ts.get_available_actions({'status': 'closed'}, perm))
+
+    def test_available_actions_no_perms(self):
+        ts = TicketSystem(self.env)
+        perm = Mock(has_permission=lambda x: 0)
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'new'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'assigned'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'reopened'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'closed'}, perm))
+
+    def test_available_actions_create_only(self):
+        ts = TicketSystem(self.env)
+        perm = Mock(has_permission=lambda x: x == 'TICKET_CREATE')
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'new'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'assigned'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'reopened'}, perm))
+        self.assertEqual(['leave', 'reopen'],
+                         ts.get_available_actions({'status': 'closed'}, perm))
+
+    def test_available_actions_chgprop_only(self):
+        # CHGPROP is not enough for changing a ticket's state (#3289)
+        ts = TicketSystem(self.env)
+        perm = Mock(has_permission=lambda x: x == 'TICKET_CHGPROP')
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'new'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'assigned'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'reopened'}, perm))
+        self.assertEqual(['leave'],
+                         ts.get_available_actions({'status': 'closed'}, perm))
+
+
+def suite():
+    return unittest.makeSuite(TicketSystemTestCase, 'test')
+
+if __name__ == '__main__':
+    unittest.main()