Enabling text search with MongoEngine.

models.py

from mongoengine import Document, StringField, IntField, BooleanField

class MockDocument(Document):
  name = StringField(required=True, unique=True)
  number = IntField()
  fact = BooleanField()
  
  meta = {
    'allow_inheritance': True,    # Triggers the issue
    'indexes': [
      {
        'fields': ['$name'],
        'cls': False              # Solves the issue
      }
    ]
  }

test_models.py

import unittest

class MockDocumentIntegrationTests(unittest.TestCase):
  
  TEST_DB = 'test'
  
  @classmethod
  def setUp(cls):
    import mongoengine
    db = mongoengine.connect(cls.TEST_DB)
    db.drop_database(cls.TEST_DB)
    
  def setUp(self):
    from models import MockDocument
    MockDocument.drop_collection()

    def test_search_text_returns_matching_documents(self):
        """A search_text() query returns matching MockDocument instances
        """
        names = [
            'Some Important Document',
            'Some Other Document',
            'Another Important Document']
        from ..models import MockDocument
        for name in names:
            MockDocument(name=name).save()
        docs = MockDocument.objects.search_text('important').all()
        expected = {
            'Some Important Document',
            'Another Important Document'}
        results = {d.name for d in docs}
        self.assertEqual(expected, results)

    def test_raw_text_search_returns_matching_documents(self):
        """A raw text search query returns matching MockDocument instances
        """
        names = [
            'Some Important Document',
            'Some Other Document',
            'Another Important Document']
        from ..models import MockDocument
        for name in names:
            MockDocument(name=name).save()
        raw_query = {'$text': {'$search': 'important'}}
        docs = MockDocument.objects(__raw__=raw_query).all()
        expected = {
            'Some Important Document',
            'Another Important Document'}
        results = {d.name for d in docs}
        self.assertEqual(expected, results)