diff --git a/Changelog.md b/Changelog.md
index 3d980d3176..b2b8c34d97 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -28,6 +28,7 @@
 - Fix: include original total mark in JSON response for remark requests (#7945)
 
 ### 🔧 Internal changes
+- Added tests for `MarksGradersController` to achieve full test coverage for `randomly_assign` (#7947)
 - Fixed flaky test `can bulk assign duplicated TAs to grade entry students` in `/spec/models/grade_entry_student_spec.rb` (#7958)
 - Added tests for `GroupsController` to fully cover `global_actions` (#7955)
 - Added tests for `graders_controller` to fully cover `grader_criteria_mapping` function (#7949)
diff --git a/doc/markus-contributors.txt b/doc/markus-contributors.txt
index 58c39f6d41..d76f2e415d 100644
--- a/doc/markus-contributors.txt
+++ b/doc/markus-contributors.txt
@@ -58,6 +58,7 @@ Clément Delafargue
 Clément Schiano
 Danesh Dadachanji
 Daniel Dervishi
+Daniel Rafailov
 Daniel St. Jules
 Daniyal Liaqat
 Daryn Lam
diff --git a/spec/controllers/marks_graders_controller_spec.rb b/spec/controllers/marks_graders_controller_spec.rb
index 2a590ec2b5..6aa07884b3 100644
--- a/spec/controllers/marks_graders_controller_spec.rb
+++ b/spec/controllers/marks_graders_controller_spec.rb
@@ -376,4 +376,115 @@
       end
     end
   end
+
+  describe '#randomly_assign' do
+    context 'does not require initial setup' do
+      context 'when students and graders are selected' do
+        it 'calls GradeEntryStudent `randomly_assign_tas` and ensures that every student gets a TA assigned to them' do
+          tas = create_list(:ta, 3)
+          ta_ids = tas.map(&:id)
+
+          students = create_list(:student, 10, course: course)
+          student_ids = students.map(&:id)
+
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            students: student_ids,
+            graders: ta_ids
+          }
+
+          expect(response).to have_http_status(:ok)
+
+          students.each do |student|
+            ges = grade_entry_form.grade_entry_students.find_by!(role: student.id)
+            expect(ges.tas.count).to eq(1)
+          end
+        end
+      end
+    end
+
+    context 'requires initial setup' do
+      before do
+        allow(GradeEntryStudent).to receive(:randomly_assign_tas)
+      end
+
+      context 'when students and graders are selected' do
+        it 'calls GradeEntryStudent `randomly_assign_tas` and returns a success response' do
+          student = create(:student)
+          grade_entry_student = grade_entry_form.grade_entry_students.find_by(role: student)
+          grade_entry_student_ta = create(:grade_entry_student_ta, grade_entry_student: grade_entry_student)
+
+          expect(GradeEntryStudent).to receive(:randomly_assign_tas).with(
+            [grade_entry_student.id.to_s],
+            [grade_entry_student_ta.id.to_s],
+            grade_entry_form
+          )
+
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            students: [grade_entry_student.id],
+            graders: [grade_entry_student_ta.id]
+          }
+
+          expect(response).to have_http_status(:ok)
+        end
+      end
+
+      context 'when students are not selected' do
+        it 'returns bad request and sets a flash error' do
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            students: [],
+            graders: [1]
+          }
+
+          expect(response).to have_http_status(:bad_request)
+          expect(flash[:error]).to have_message(I18n.t('groups.select_a_student'))
+        end
+      end
+
+      context 'when graders are not selected' do
+        it 'returns bad request and sets flash error' do
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            students: [1],
+            graders: []
+          }
+
+          expect(response).to have_http_status(:bad_request)
+          expect(flash[:error]).to have_message(I18n.t('graders.select_a_grader'))
+        end
+      end
+
+      context 'when students parameter is missing' do
+        it 'returns bad request and sets flash error' do
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            graders: [1]
+          }
+
+          expect(response).to have_http_status(:bad_request)
+          expect(flash[:error]).to have_message(I18n.t('groups.select_a_student'))
+        end
+      end
+
+      context 'when graders parameter is missing' do
+        it 'returns bad request and sets flash error' do
+          post_as instructor, :randomly_assign, params: {
+            course_id: course.id,
+            grade_entry_form_id: grade_entry_form.id,
+            students: [1]
+          }
+
+          expect(response).to have_http_status(:bad_request)
+          expect(flash[:error]).to have_message(I18n.t('graders.select_a_grader'))
+        end
+      end
+    end
+  end
 end
diff --git a/spec/models/grade_entry_student_spec.rb b/spec/models/grade_entry_student_spec.rb
index b79704cfd8..b998f4d119 100644
--- a/spec/models/grade_entry_student_spec.rb
+++ b/spec/models/grade_entry_student_spec.rb
@@ -84,7 +84,7 @@
         GradeEntryStudent.assign_all_tas(student_ids, ta_ids.first, form)
 
         # First grade entry student gets all the TAs.
-        grade_entry_student = form.grade_entry_students.find_by!(role_id: student_ids.first)
+        grade_entry_student = form.grade_entry_students.first
         grade_entry_student.reload
         form.grade_entry_students.delete(grade_entry_student)
         expect(grade_entry_student.tas).to match_array(tas)