Fix that don't allow Publisher to add negative prices for course run certificates.

course_discovery/apps/publisher/forms.py

@@ -384,7 +384,7 @@ class SeatForm(BaseForm):
     ]
 
     type = forms.ChoiceField(choices=TYPE_CHOICES, required=False, label=_('Enrollment Track'))
-    price = forms.DecimalField(max_digits=6, decimal_places=2, required=False, initial=0.00)
+    price = forms.DecimalField(max_digits=6, min_value=0.01, decimal_places=2, required=False, initial=0.00)
     credit_price = forms.DecimalField(max_digits=6, decimal_places=2, required=False, initial=0.00)
 
     class Meta:
@@ -458,7 +458,7 @@ class CourseEntitlementForm(BaseForm):
 
     mode = forms.ChoiceField(choices=MODE_CHOICES, required=False, label=_('Enrollment Track'),
                              initial=CourseEntitlement.VERIFIED)
-    price = forms.DecimalField(max_digits=6, decimal_places=2, required=False, initial=0.00)
+    price = forms.DecimalField(max_digits=6, min_value=0.01, decimal_places=2, required=False, initial=0.00)
 
     class Meta:
         fields = ('mode', 'price')

course_discovery/apps/publisher/tests/test_forms.py

@@ -391,6 +391,17 @@ class PublisherCourseEntitlementFormTests(TestCase):
 
         self.assertEqual(entitlement_form.clean(), entitlement_form.cleaned_data)
 
+    def test_negative_price(self):
+        """
+        Verify that form raises an error when price is in -ive
+        """
+        form_data = {'mode': CourseEntitlement.VERIFIED, 'price': -0.05}
+        entitlement_form = CourseEntitlementForm(data=form_data)
+        self.assertFalse(entitlement_form.is_valid())
+        self.assertEqual(entitlement_form.errors,
+                         {'price': ['Ensure this value is greater than or equal to 0.01.', '']}
+                         )
+
 
 @pytest.mark.django_db
 class TestSeatForm: