Doc/test SearchFilter m2m behavior

tests/test_filters_multiple.py

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+import datetime
+
+from django.db import models
+from django.test import TestCase
+
+from rest_framework import filters, generics, serializers
+from rest_framework.test import APIRequestFactory
+
+factory = APIRequestFactory()
+
+
+class Post(models.Model):
+    name = models.CharField(max_length=20)
+
+
+class Author(models.Model):
+    name = models.CharField(max_length=20)
+
+
+class EntryRecord(models.Model):
+    blog = models.ForeignKey(Post, on_delete=models.CASCADE)
+    authors = models.ManyToManyField(Author, related_name='entries', blank=True)
+    headline = models.CharField(max_length=120)
+    pub_date = models.DateField(null=True)
+
+
+class PostSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Post
+        fields = '__all__'
+
+
+class EntryRecordSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = EntryRecord
+        fields = '__all__'
+
+
+class SearchFilterToManyTests(TestCase):
+
+    @classmethod
+    def setUpTestData(cls):
+        b1 = Post.objects.create(name='Post 1')
+        b2 = Post.objects.create(name='Post 2')
+
+        a1 = Author.objects.create(name='alice')
+        a2 = Author.objects.create(name='bob')
+
+        # Multiple entries on Lennon published in 1979 - distinct should deduplicate
+        e1 = EntryRecord.objects.create(blog=b1, headline='Something about Lennon', pub_date=datetime.date(1979, 1, 1))
+        e1.authors.add(a1)
+        e1.save()
+
+        e2 = EntryRecord.objects.create(blog=b1, headline='Another thing about Lennon', pub_date=datetime.date(1979, 6, 1))
+        e2.authors.add(a2)
+        e2.save()
+
+        # EntryRecord on Lennon *and* a separate entryrecord in 1979 - should not match
+        e3 = EntryRecord.objects.create(blog=b2, headline='Something unrelated', pub_date=datetime.date(1979, 1, 1))
+
+        e4 = EntryRecord.objects.create(blog=b2, headline='Retrospective on Lennon', pub_date=datetime.date(1990, 6, 1))
+        e4.authors.add(a1)
+        e4.authors.add(a2)
+        e4.save()
+
+    def setUp(self):
+        class SearchPostListView(generics.ListAPIView):
+            queryset = Post.objects.all()
+            serializer_class = PostSerializer
+            filter_backends = (filters.SearchFilter,)
+            search_fields = (
+                '=name',
+                'entryrecord__headline',
+                '=entryrecord__pub_date__year',
+                'entryrecord__authors__name'
+            )
+
+        self.SearchPostListView = SearchPostListView
+
+        class SearchEntryRecordListView(generics.ListAPIView):
+            queryset = EntryRecord.objects.all()
+            serializer_class = EntryRecordSerializer
+            filter_backends = (filters.SearchFilter,)
+            search_fields = (
+                'authors__name',
+            )
+
+        self.SearchEntryRecordListView = SearchEntryRecordListView
+
+    def test_multiple_filter_conditions(self):
+        view = self.SearchPostListView.as_view()
+        request = factory.get('/', {'search': 'Lennon, 1979'})
+        response = view(request)
+        assert len(response.data) == 1
+
+    def test_single_filter_condition_manytomany(self):
+        view = self.SearchPostListView.as_view()
+
+        request = factory.get('/', {'search': 'alice'})
+        response = view(request)
+        assert len(response.data) == 2
+
+        request = factory.get('/', {'search': 'bob'})
+        response = view(request)
+        assert len(response.data) == 2
+
+    def test_multiple_filter_conditions_manytomany(self):
+        view = self.SearchEntryRecordListView.as_view()
+        request = factory.get('/', {'search': 'alice, bob'})
+        response = view(request)
+        assert len(response.data) == 1
+
+        dual_entry = EntryRecord.objects.get(headline='Retrospective on Lennon')
+        response_id = response.data[0].get('id')
+        assert response_id == dual_entry.id