old_contents: from unittest import TestCase
  
  from mockfirestore import MockFirestore
  
  
  class TestDocumentSnapshot(TestCase):
      def test_documentSnapshot_toDict(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('first').get()
          self.assertEqual({'id': 1}, doc.to_dict())
  
      def test_documentSnapshot_exists(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('first').get()
          self.assertTrue(doc.exists)
  
      def test_documentSnapshot_exists_documentDoesNotExist(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('second').get()
          self.assertFalse(doc.exists)
  
new_contents: from unittest import TestCase
  
  from mockfirestore import MockFirestore
  
  
  class TestDocumentSnapshot(TestCase):
      def test_documentSnapshot_toDict(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('first').get()
          self.assertEqual({'id': 1}, doc.to_dict())
  
      def test_documentSnapshot_exists(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('first').get()
          self.assertTrue(doc.exists)
  
      def test_documentSnapshot_exists_documentDoesNotExist(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc = fs.collection('foo').document('second').get()
          self.assertFalse(doc.exists)
  
      def test_documentSnapshot_reference(self):
          fs = MockFirestore()
          fs._data = {'foo': {
              'first': {'id': 1}
          }}
          doc_ref = fs.collection('foo').document('second')
          doc_snapshot = doc_ref.get()
          self.assertIs(doc_ref, doc_snapshot.reference)
  
  
subject: Add test for DocumentSnapshot.reference