Allow previewing cohorted content when masquerading

common/test/acceptance/pages/lms/staff_view.py

@@ -33,6 +33,19 @@ class StaffPage(CoursewarePage):
         self.q(css=self.VIEW_MODE_OPTIONS_CSS).filter(lambda el: el.text == view_mode).first.click()
         self.wait_for_ajax()
 
+    def set_staff_view_mode_specific_student(self, username_or_email):
+        """
+        Set the current preview mode to "Specific Student" with the given username or email
+        """
+        required_mode = "Specific student"
+        if self.staff_view_mode != required_mode:
+            self.q(css=self.VIEW_MODE_OPTIONS_CSS).filter(lambda el: el.text == required_mode).first.click()
+        # Use a script here because .clear() + .send_keys() triggers unwanted behavior if a username is already set
+        self.browser.execute_script(
+            '$(".action-preview-username").val("{}").blur().change();'.format(username_or_email)
+        )
+        self.wait_for_ajax()
+
     def open_staff_debug_info(self):
         """
         Open the staff debug window

common/test/acceptance/tests/lms/test_lms_user_preview.py

@@ -6,8 +6,10 @@ Tests the "preview" selector in the LMS that allows changing between Staff, Stud
 from ..helpers import UniqueCourseTest, create_user_partition_json
 from ...pages.studio.auto_auth import AutoAuthPage
 from ...pages.lms.courseware import CoursewarePage
+from ...pages.lms.instructor_dashboard import InstructorDashboardPage
 from ...pages.lms.staff_view import StaffPage
 from ...fixtures.course import CourseFixture, XBlockFixtureDesc
+from bok_choy.promise import EmptyPromise
 from xmodule.partitions.partitions import Group
 from textwrap import dedent
 
@@ -335,6 +337,44 @@ class CourseWithContentGroupsTest(StaffViewTest):
         course_page.set_staff_view_mode('Student in beta')
         verify_expected_problem_visibility(self, course_page, [self.beta_text, self.everyone_text])
 
+    def create_cohorts_and_assign_students(self, student_a_username, student_b_username):
+        """
+        Adds 2 manual cohorts, linked to content groups, to the course.
+        Each cohort is assigned one student.
+        """
+        instructor_dashboard_page = InstructorDashboardPage(self.browser, self.course_id)
+        instructor_dashboard_page.visit()
+        cohort_management_page = instructor_dashboard_page.select_cohort_management()
+        cohort_management_page.is_cohorted = True
+
+        def add_cohort_with_student(cohort_name, content_group, student):
+            """ Create cohort and assign student to it. """
+            cohort_management_page.add_cohort(cohort_name, content_group=content_group)
+            # After adding the cohort, it should automatically be selected
+            EmptyPromise(
+                lambda: cohort_name == cohort_management_page.get_selected_cohort(), "Waiting for new cohort"
+            ).fulfill()
+            cohort_management_page.add_students_to_selected_cohort([student])
+        add_cohort_with_student("Cohort Alpha", "alpha", student_a_username)
+        add_cohort_with_student("Cohort Beta", "beta", student_b_username)
+        cohort_management_page.wait_for_ajax()
+
+    def test_as_specific_student(self):
+        student_a_username = 'tass_student_a'
+        student_b_username = 'tass_student_b'
+        AutoAuthPage(self.browser, username=student_a_username, course_id=self.course_id, no_login=True).visit()
+        AutoAuthPage(self.browser, username=student_b_username, course_id=self.course_id, no_login=True).visit()
+        self.create_cohorts_and_assign_students(student_a_username, student_b_username)
+
+        # Masquerade as student in alpha cohort:
+        course_page = self._goto_staff_page()
+        course_page.set_staff_view_mode_specific_student(student_a_username)
+        verify_expected_problem_visibility(self, course_page, [self.alpha_text, self.everyone_text])
+
+        # Masquerade as student in beta cohort:
+        course_page.set_staff_view_mode_specific_student(student_b_username)
+        verify_expected_problem_visibility(self, course_page, [self.beta_text, self.everyone_text])
+
 
 def verify_expected_problem_visibility(test, courseware_page, expected_problems):
     """