Fix: Unhelpful tooltips shown in sequential accordion in the LMS

problem_builder/mentoring.py

@@ -759,10 +759,16 @@ class MentoringBlock(XBlock, StepParentMixin, StudioEditableXBlockMixin, StudioC
         """
         By default, each Sequential block in a course ("Subsection" in Studio parlance) will
         display the display_name of each descendant in a tooltip above the content. We don't
-        want that - we only want to display the mentoring block as a whole as one item.
+        want that - we only want to display one title for this mentoring block as a whole.
         Otherwise things like "Choice (yes) (Correct)" will appear in the tooltip.
+
+        If this block has no title set, don't display any title. Then, if this is the only block
+        in the unit, the unit's title will be used. (Why isn't it always just used?)
         """
-        return [self.display_name]
+        has_explicitly_set_title = self.fields['display_name'].is_set_on(self)
+        if has_explicitly_set_title:
+            return [self.display_name]
+        return []
 
     @staticmethod
     def workbench_scenarios():

problem_builder/tests/unit/test_mentoring.py

@@ -6,6 +6,7 @@ from problem_builder import MentoringBlock
 from problem_builder.mentoring import _default_theme_config
 
 
+@ddt.ddt
 class TestMentoringBlock(unittest.TestCase):
     def test_sends_progress_event_when_rendered_student_view_with_display_submit_false(self):
         block = MentoringBlock(MagicMock(), DictFieldData({
@@ -31,6 +32,21 @@ class TestMentoringBlock(unittest.TestCase):
 
             self.assertFalse(patched_runtime.publish.called)
 
+    @ddt.data(True, False)
+    def test_get_content_titles(self, has_title_set):
+        """
+        Test that we don't send a title to the LMS for the sequential's tooltips when no title
+        is set
+        """
+        if has_title_set:
+            data = {'display_name': 'Custom Title'}
+            expected = ['Custom Title']
+        else:
+            data = {}
+            expected = []
+        block = MentoringBlock(MagicMock(), DictFieldData(data), Mock())
+        self.assertEqual(block.get_content_titles(), expected)
+
 
 @ddt.ddt
 class TestMentoringBlockTheming(unittest.TestCase):