diff --git a/lms/djangoapps/discussion_api/tests/test_forms.py b/lms/djangoapps/discussion_api/tests/test_forms.py
index ab09f0b969..cd841e9fcc 100644
--- a/lms/djangoapps/discussion_api/tests/test_forms.py
+++ b/lms/djangoapps/discussion_api/tests/test_forms.py
@@ -100,14 +100,20 @@ class ThreadListGetFormTest(FormTestMixin, PaginationTestMixin, TestCase):
         self.form_data.setlist("topic_id", ["", "not empty"])
         self.assert_error("topic_id", "This field cannot be empty.")
 
-    def test_following_true(self):
-        self.form_data["following"] = "True"
+    @ddt.data("True", "true", 1, True)
+    def test_following_true(self, value):
+        self.form_data["following"] = value
         self.assert_field_value("following", True)
 
-    def test_following_false(self):
-        self.form_data["following"] = "False"
+    @ddt.data("False", "false", 0, False)
+    def test_following_false(self, value):
+        self.form_data["following"] = value
         self.assert_error("following", "The value of the 'following' parameter must be true.")
 
+    def test_invalid_following(self):
+        self.form_data["following"] = "invalid-boolean"
+        self.assert_error("following", "Invalid Boolean Value.")
+
     @ddt.data(*itertools.combinations(["topic_id", "text_search", "following"], 2))
     def test_mutually_exclusive(self, params):
         self.form_data.update({param: "True" for param in params})
@@ -134,7 +140,22 @@ class ThreadListGetFormTest(FormTestMixin, PaginationTestMixin, TestCase):
             "Select a valid choice. not_a_valid_choice is not one of the available choices."
         )
 
+    @ddt.data(
+        ("view", "unread"),
+        ("view", "unanswered"),
+        ("order_by", "last_activity_at"),
+        ("order_by", "comment_count"),
+        ("order_by", "vote_count"),
+        ("order_direction", "asc"),
+        ("order_direction", "desc"),
+    )
+    @ddt.unpack
+    def test_valid_choice_fields(self, field, value):
+        self.form_data[field] = value
+        self.assert_field_value(field, value)
 
+
+@ddt.ddt
 class CommentListGetFormTest(FormTestMixin, PaginationTestMixin, TestCase):
     """Tests for CommentListGetForm"""
     FORM_CLASS = CommentListGetForm
@@ -167,3 +188,17 @@ class CommentListGetFormTest(FormTestMixin, PaginationTestMixin, TestCase):
     def test_missing_endorsed(self):
         self.form_data.pop("endorsed")
         self.assert_field_value("endorsed", None)
+
+    @ddt.data("True", "true", True, 1)
+    def test_endorsed_true(self, value):
+        self.form_data["endorsed"] = value
+        self.assert_field_value("endorsed", True)
+
+    @ddt.data("False", "false", False, 0)
+    def test_endorsed_false(self, value):
+        self.form_data["endorsed"] = value
+        self.assert_field_value("endorsed", False)
+
+    def test_invalid_endorsed(self):
+        self.form_data["endorsed"] = "invalid-boolean"
+        self.assert_error("endorsed", "Invalid Boolean Value.")
diff --git a/lms/djangoapps/discussion_api/tests/test_views.py b/lms/djangoapps/discussion_api/tests/test_views.py
index 44dcde6def..2727566877 100644
--- a/lms/djangoapps/discussion_api/tests/test_views.py
+++ b/lms/djangoapps/discussion_api/tests/test_views.py
@@ -1014,6 +1014,39 @@ class CommentViewSetListTest(DiscussionAPIViewTestMixin, ModuleStoreTestCase):
         parsed_content = json.loads(response.content)
         self.assertEqual(parsed_content["results"][0]["id"], comment_id)
 
+    def test_question_invalid_endorsed(self):
+        response = self.client.get(self.url, {
+            "thread_id": self.thread_id,
+            "endorsed": "invalid-boolean"
+        })
+        self.assert_response_correct(
+            response,
+            400,
+            {"field_errors": {
+                "endorsed": {"developer_message": "Invalid Boolean Value."}
+            }}
+        )
+
+    def test_question_missing_endorsed(self):
+        self.register_get_user_response(self.user)
+        thread = self.make_minimal_cs_thread({
+            "thread_type": "question",
+            "endorsed_responses": [make_minimal_cs_comment({"id": "endorsed_comment"})],
+            "non_endorsed_responses": [make_minimal_cs_comment({"id": "non_endorsed_comment"})],
+            "non_endorsed_resp_total": 1,
+        })
+        self.register_get_thread_response(thread)
+        response = self.client.get(self.url, {
+            "thread_id": thread["id"]
+        })
+        self.assert_response_correct(
+            response,
+            400,
+            {"field_errors": {
+                "endorsed": {"developer_message": "This field is required for question threads."}
+            }}
+        )
+
 
 @httpretty.activate
 @disable_signal(api, 'comment_deleted')