Revert "Revert "refactor: move common/lib/capa/capa to xmodule/capa" (#30762)"

This reverts commit 4463ee751d.

xmodule/capa/tests/test_xqueue_interface.py

@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*-
+"""
+Tests the xqueue service interface.
+"""
+
+from unittest import TestCase
+from django.conf import settings
+
+from xmodule.capa.xqueue_interface import XQueueInterface, XQueueService
+
+
+class XQueueServiceTest(TestCase):
+    """
+    Tests the XQueue service methods.
+    """
+    @staticmethod
+    def construct_callback(*args, **kwargs):
+        return 'https://lms.url/callback'
+
+    def setUp(self):
+        super().setUp()
+        self.service = XQueueService(
+            url=settings.XQUEUE_INTERFACE['url'],
+            django_auth=settings.XQUEUE_INTERFACE['django_auth'],
+            basic_auth=settings.XQUEUE_INTERFACE['basic_auth'],
+            construct_callback=self.construct_callback,
+            default_queuename='my-very-own-queue',
+            waittime=settings.XQUEUE_WAITTIME_BETWEEN_REQUESTS,
+        )
+
+    def test_interface(self):
+        assert isinstance(self.service.interface, XQueueInterface)
+
+    def test_construct_callback(self):
+        assert self.service.construct_callback() == 'https://lms.url/callback'
+
+    def test_default_queuename(self):
+        assert self.service.default_queuename == 'my-very-own-queue'
+
+    def test_waittime(self):
+        assert self.service.waittime == 5