Fix the form for adopting a project

readthedocs/gold/forms.py

@@ -6,6 +6,7 @@
 from django import forms
 
 from readthedocs.payments.forms import StripeModelForm, StripeResourceMixin
+from readthedocs.projects.models import Project
 
 from .models import LEVEL_CHOICES, GoldUser
 
@@ -90,7 +91,13 @@ def __init__(self, *args, **kwargs):
 
     def clean(self):
         cleaned_data = super(GoldProjectForm, self).clean()
+        project_slug = cleaned_data.get('project', "")
         if self.projects.count() < self.user.num_supported_projects:
-            return cleaned_data
-
-        self.add_error(None, 'You already have the max number of supported projects.')
+            # Checking if the project with the entered slug
+            # is present in the database or not
+            if Project.objects.filter(slug=project_slug).exists():
+                return cleaned_data
+            if project_slug:
+                self.add_error(None, "No project found.")
+        else:
+            self.add_error(None, 'You already have the max number of supported projects.')

readthedocs/rtd_tests/tests/test_gold.py

@@ -26,6 +26,13 @@ def test_adding_projects(self):
         self.assertEqual(self.golduser.projects.count(), 1)
         self.assertEqual(resp.status_code, 302)
 
+    def test_incorrect_input_when_adding_projects(self):
+        self.assertEqual(self.golduser.projects.count(), 0)
+        resp = self.client.post(reverse('gold_projects'), data={'project': 'random-incorrect-slug'})
+        self.assertFormError(
+            resp, form='form', field=None, errors='No project found.'
+        )
+
     def test_too_many_projects(self):
         self.project2 = get(Project, slug='test2')