feat: Added validations for question doctype

- A question must have more than two options
- A question must have at least one correct option

erpnext/education/doctype/question/question.py

@@ -4,10 +4,28 @@
 
 from __future__ import unicode_literals
 import frappe
+from frappe import _
 from frappe.model.document import Document
 
 class Question(Document):
 
+	def validate(self):
+		self.check_at_least_one_option()
+		self.check_minimum_one_correct_answer()
+
+	def check_at_least_one_option(self):
+		if len(self.get_all_children()) <= 1:
+			frappe.throw(_("A question must have more than one options"))
+		else:
+			pass
+
+	def check_minimum_one_correct_answer(self):
+		correct_options = [question.is_correct for question in self.get_all_children()]
+		if bool(sum(correct_options)):
+			pass
+		else:
+			frappe.throw(_("A qustion must have at least one correct options"))
+
 	def get_answer(self):
 		options = self.get_all_children()
 		answers = [item.name for item in options if item.is_correct == True]