add tests for get_first_unfinished_part

stories/writingtogether/tests/test_model_functions.py

@@ -0,0 +1,88 @@
+from typing import List
+
+from django.contrib.auth import get_user_model
+from django.test import TestCase
+
+from writingtogether.models import StoryRound, Story, StoryPart
+
+User = get_user_model()
+
+class TestModelFunctions(TestCase):
+
+    def create_users_and_story_round_with_stories_and_parts(self):
+        self.user1 = User.objects.create(username='player1')
+        self.user2 = User.objects.create(username='player2')
+
+        self.story_round = StoryRound.objects.create(
+            name='test_round',
+            number_of_rounds=4
+        )
+        self.story_round.participants.add(self.user1)
+        self.story_round.participants.add(self.user2)
+
+        self.story1 = Story.objects.create(
+            name='story1',
+            part_of_round=self.story_round,
+            started_by=self.user1,
+        )
+
+        self.story2 = Story.objects.create(
+            name='story2',
+            part_of_round=self.story_round,
+            started_by=self.user2,
+        )
+
+        self.parts1 = self.create_story_parts(self.story1, users=[self.user1, self.user2], num_rounds=4)
+        self.parts2 = self.create_story_parts(self.story2, users=[self.user1, self.user2], num_rounds=4,
+                                              first_user_index=1)
+
+    def create_story_parts(
+            self, story: Story, users: List[User],
+            num_rounds: int, first_user_index: int = 0
+    ) -> List[StoryPart]:
+        parts = []
+        previous_part = None
+        for i in range(num_rounds):
+            user = users[(first_user_index + i) % len(users)]
+            new_part = StoryPart.objects.create(
+                user=user,
+                previous_part=previous_part,
+                part_of=story
+            )
+            parts.append(new_part)
+            previous_part = new_part
+
+        return parts
+
+    def test_get_first_unfinished_part__nothing_written(self):
+        self.create_users_and_story_round_with_stories_and_parts()
+
+        result = self.story1.get_first_unfinished_part()
+
+        self.assertEqual(result, self.parts1[0])
+
+    def test_get_first_unfinished_part__one_written(self):
+        self.create_users_and_story_round_with_stories_and_parts()
+        self.parts1[0].text = 'some text'
+        self.parts1[0].save()
+
+        result = self.story1.get_first_unfinished_part()
+
+        self.assertEqual(result, self.parts1[1])
+
+    def test_get_first_unfinished_part__finished(self):
+        self.create_users_and_story_round_with_stories_and_parts()
+        self.parts1[0].text = 'some text'
+        self.parts1[0].save()
+        self.parts1[1].text = 'some text'
+        self.parts1[1].save()
+        self.parts1[2].text = 'some text'
+        self.parts1[2].save()
+        self.parts1[3].text = 'some text'
+        self.parts1[3].save()
+        self.story1.finished = True
+        self.story1.save()
+
+        result = self.story1.get_first_unfinished_part()
+
+        self.assertEqual(result, None)