core/domain/recommendations_services_test.py - develop - githubmirror/oppia

core/domain/recommendations_services_test.py
431 строка20 KB
ateeksh22
Fix #26623: Migrate datetime usage to utils functions (#26648)
05 авг 2026, 07:42
05 авг 2026, 07:421d13470
# coding: utf-8
#
# Copyright 2015 The Oppia Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS-IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Unit tests for recommendations_services."""

from __future__ import annotations

import datetime

from core import feconf, utils
from core.domain import (
    exp_services,
    recommendations_services,
    rights_manager,
    user_services,
)
from core.platform import models
from core.tests import test_utils

from typing import Dict, Final

MYPY = False
if MYPY:  # pragma: no cover
    from mypy_imports import recommendations_models

(recommendations_models,) = models.Registry.import_models(
    [models.Names.RECOMMENDATIONS]
)


class TopicSimilarityUnitTests(test_utils.GenericTestBase):
    """Tests of the recommendation services module."""

    # pylint: disable=line-too-long, single-line-pragma
    TOPIC_SIMILARITIES_DEFAULT: Final = (
        """Architecture,Art,Biology,Business,Chemistry,Computing,Economics,Education,Engineering,Environment,Geography,Government,Hobbies,Languages,Law,Life Skills,Mathematics,Medicine,Music,Philosophy,Physics,Programming,Psychology,Puzzles,Reading,Religion,Sport,Statistics,Welcome
1.0,0.9,0.2,0.4,0.1,0.2,0.3,0.3,0.6,0.6,0.4,0.2,0.5,0.5,0.5,0.3,0.5,0.3,0.3,0.5,0.4,0.1,0.6,0.1,0.1,0.1,0.1,0.1,0.3
0.9,1.0,0.1,0.6,0.1,0.1,0.6,0.6,0.2,0.3,0.3,0.2,0.5,0.7,0.6,0.2,0.3,0.2,0.9,0.7,0.3,0.1,0.6,0.1,0.1,0.1,0.1,0.1,0.3
0.2,0.1,1.0,0.2,0.8,0.3,0.2,0.3,0.3,0.7,0.4,0.2,0.2,0.1,0.1,0.9,0.4,0.8,0.1,0.1,0.4,0.1,0.6,0.1,0.1,0.1,0.1,0.6,0.3
0.4,0.6,0.2,1.0,0.1,0.5,0.9,0.6,0.4,0.6,0.2,0.7,0.2,0.5,0.7,0.1,0.3,0.1,0.1,0.6,0.1,0.2,0.3,0.1,0.1,0.1,0.1,0.5,0.3
0.1,0.1,0.8,0.1,1.0,0.2,0.2,0.3,0.2,0.6,0.6,0.1,0.2,0.2,0.2,0.7,0.3,0.7,0.1,0.1,0.2,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.3
0.2,0.1,0.3,0.5,0.2,1.0,0.6,0.3,0.6,0.1,0.1,0.1,0.2,0.2,0.1,0.3,0.9,0.2,0.2,0.3,0.4,0.95,0.3,0.5,0.1,0.1,0.1,0.6,0.3
0.3,0.6,0.2,0.9,0.2,0.6,1.0,0.3,0.3,0.5,0.4,0.7,0.2,0.4,0.8,0.2,0.6,0.2,0.1,0.3,0.1,0.3,0.6,0.3,0.2,0.1,0.1,0.7,0.3
0.3,0.6,0.3,0.6,0.3,0.3,0.3,1.0,0.3,0.5,0.3,0.5,0.2,0.2,0.6,0.1,0.2,0.1,0.1,0.5,0.1,0.1,0.6,0.1,0.3,0.2,0.2,0.2,0.3
0.6,0.2,0.3,0.4,0.2,0.6,0.3,0.3,1.0,0.4,0.2,0.2,0.2,0.2,0.3,0.1,0.7,0.1,0.1,0.3,0.6,0.6,0.2,0.3,0.1,0.1,0.1,0.5,0.3
0.6,0.3,0.7,0.6,0.6,0.1,0.5,0.5,0.4,1.0,0.8,0.6,0.2,0.2,0.3,0.8,0.2,0.3,0.1,0.2,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.3
0.4,0.3,0.4,0.2,0.6,0.1,0.4,0.3,0.2,0.8,1.0,0.2,0.2,0.4,0.3,0.6,0.3,0.3,0.1,0.1,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.2,0.3
0.2,0.2,0.2,0.7,0.1,0.1,0.7,0.5,0.2,0.6,0.2,1.0,0.2,0.3,0.8,0.1,0.1,0.1,0.1,0.4,0.1,0.1,0.4,0.1,0.5,0.5,0.2,0.4,0.3
0.5,0.5,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,1.0,0.5,0.2,0.2,0.3,0.2,0.4,0.2,0.3,0.5,0.2,0.6,0.5,0.3,0.6,0.2,0.3
0.5,0.7,0.1,0.5,0.2,0.2,0.4,0.2,0.2,0.2,0.4,0.3,0.5,1.0,0.3,0.1,0.1,0.1,0.3,0.4,0.1,0.1,0.3,0.1,0.8,0.4,0.1,0.1,0.3
0.5,0.6,0.1,0.7,0.2,0.1,0.8,0.6,0.3,0.3,0.3,0.8,0.2,0.3,1.0,0.1,0.1,0.1,0.1,0.6,0.1,0.1,0.6,0.1,0.4,0.6,0.1,0.2,0.3
0.3,0.2,0.9,0.1,0.7,0.3,0.2,0.1,0.1,0.8,0.6,0.1,0.2,0.1,0.1,1.0,0.4,0.8,0.1,0.2,0.2,0.2,0.3,0.1,0.2,0.1,0.3,0.4,0.3
0.5,0.3,0.4,0.3,0.3,0.9,0.6,0.2,0.7,0.2,0.3,0.1,0.3,0.1,0.1,0.4,1.0,0.2,0.3,0.4,0.7,0.8,0.2,0.6,0.1,0.1,0.1,0.8,0.3
0.3,0.2,0.8,0.1,0.7,0.2,0.2,0.1,0.1,0.3,0.3,0.1,0.2,0.1,0.1,0.8,0.2,1.0,0.2,0.3,0.1,0.2,0.3,0.1,0.1,0.1,0.1,0.1,0.3
0.3,0.9,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.1,0.1,0.1,0.4,0.3,0.1,0.1,0.3,0.2,1.0,0.6,0.3,0.2,0.4,0.1,0.3,0.1,0.1,0.1,0.3
0.5,0.7,0.1,0.6,0.1,0.3,0.3,0.5,0.3,0.2,0.1,0.4,0.2,0.4,0.6,0.2,0.4,0.3,0.6,1.0,0.3,0.6,0.4,0.5,0.2,0.1,0.1,0.3,0.3
0.4,0.3,0.4,0.1,0.2,0.4,0.1,0.1,0.6,0.1,0.1,0.1,0.3,0.1,0.1,0.2,0.7,0.1,0.3,0.3,1.0,0.6,0.1,0.5,0.2,0.1,0.3,0.4,0.3
0.1,0.1,0.1,0.2,0.1,0.95,0.3,0.1,0.6,0.1,0.1,0.1,0.5,0.1,0.1,0.2,0.8,0.2,0.2,0.6,0.6,1.0,0.3,0.6,0.1,0.1,0.1,0.6,0.3
0.6,0.6,0.6,0.3,0.3,0.3,0.6,0.6,0.2,0.3,0.3,0.4,0.2,0.3,0.6,0.3,0.2,0.3,0.4,0.4,0.1,0.3,1.0,0.4,0.3,0.3,0.2,0.4,0.3
0.1,0.1,0.1,0.1,0.1,0.5,0.3,0.1,0.3,0.1,0.1,0.1,0.6,0.1,0.1,0.1,0.6,0.1,0.1,0.5,0.5,0.6,0.4,1.0,0.1,0.1,0.1,0.5,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.3,0.1,0.1,0.1,0.5,0.5,0.8,0.4,0.2,0.1,0.1,0.3,0.2,0.2,0.1,0.3,0.1,1.0,0.4,0.1,0.1,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.5,0.3,0.4,0.6,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.3,0.1,0.4,1.0,0.2,0.1,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.2,0.6,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.1,0.2,0.1,0.1,0.2,1.0,0.3,0.3
0.1,0.1,0.6,0.5,0.3,0.6,0.7,0.2,0.5,0.3,0.2,0.4,0.2,0.1,0.2,0.4,0.8,0.1,0.1,0.3,0.4,0.6,0.4,0.5,0.1,0.1,0.3,1.0,0.3
0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,1.0"""
    )

    TOPIC_SIMILARITIES_UPDATED: Final = (
        """Architecture,Art,Biology,Business,Chemistry,Computing,Economics,Education,Engineering,Environment,Geography,Government,Hobbies,Languages,Law,Life Skills,Mathematics,Medicine,Music,Philosophy,Physics,Programming,Psychology,Puzzles,Reading,Religion,Sport,Statistics,Welcome
1.0,0.9,0.2,0.4,0.1,0.2,0.3,0.3,0.6,0.6,0.4,0.2,0.5,0.5,0.5,0.3,0.5,0.3,0.3,0.5,0.4,0.1,0.6,0.1,0.1,0.1,0.1,0.1,0.3
0.9,1.0,0.2,0.6,0.1,0.1,0.6,0.6,0.2,0.3,0.3,0.2,0.5,0.7,0.6,0.2,0.3,0.2,0.9,0.7,0.3,0.1,0.6,0.1,0.1,0.1,0.1,0.1,0.3
0.2,0.2,1.0,0.2,0.8,0.3,0.2,0.3,0.3,0.7,0.4,0.2,0.2,0.1,0.1,0.9,0.4,0.8,0.1,0.1,0.4,0.1,0.6,0.1,0.1,0.1,0.1,0.6,0.3
0.4,0.6,0.2,1.0,0.1,0.5,0.9,0.6,0.4,0.6,0.2,0.7,0.2,0.5,0.7,0.1,0.3,0.1,0.1,0.6,0.1,0.2,0.3,0.1,0.1,0.1,0.1,0.5,0.3
0.1,0.1,0.8,0.1,1.0,0.2,0.2,0.3,0.2,0.6,0.6,0.1,0.2,0.2,0.2,0.7,0.3,0.7,0.1,0.1,0.2,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.3
0.2,0.1,0.3,0.5,0.2,1.0,0.6,0.3,0.6,0.1,0.1,0.1,0.2,0.2,0.1,0.3,0.9,0.2,0.2,0.3,0.4,0.95,0.3,0.5,0.1,0.1,0.1,0.6,0.3
0.3,0.6,0.2,0.9,0.2,0.6,1.0,0.3,0.3,0.5,0.4,0.7,0.2,0.4,0.8,0.2,0.6,0.2,0.1,0.3,0.1,0.3,0.6,0.3,0.2,0.1,0.1,0.7,0.3
0.3,0.6,0.3,0.6,0.3,0.3,0.3,1.0,0.3,0.5,0.3,0.5,0.2,0.2,0.6,0.1,0.2,0.1,0.1,0.5,0.1,0.1,0.6,0.1,0.3,0.2,0.2,0.2,0.3
0.6,0.2,0.3,0.4,0.2,0.6,0.3,0.3,1.0,0.4,0.2,0.2,0.2,0.2,0.3,0.1,0.7,0.1,0.1,0.3,0.6,0.6,0.2,0.3,0.1,0.1,0.1,0.5,0.3
0.6,0.3,0.7,0.6,0.6,0.1,0.5,0.5,0.4,1.0,0.8,0.6,0.2,0.2,0.3,0.8,0.2,0.3,0.1,0.2,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.3
0.4,0.3,0.4,0.2,0.6,0.1,0.4,0.3,0.2,0.8,1.0,0.2,0.2,0.4,0.3,0.6,0.3,0.3,0.1,0.1,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.2,0.3
0.2,0.2,0.2,0.7,0.1,0.1,0.7,0.5,0.2,0.6,0.2,1.0,0.2,0.3,0.8,0.1,0.1,0.1,0.1,0.4,0.1,0.1,0.4,0.1,0.5,0.5,0.2,0.4,0.3
0.5,0.5,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,0.2,1.0,0.5,0.2,0.2,0.3,0.2,0.4,0.2,0.3,0.5,0.2,0.6,0.5,0.3,0.6,0.2,0.3
0.5,0.7,0.1,0.5,0.2,0.2,0.4,0.2,0.2,0.2,0.4,0.3,0.5,1.0,0.3,0.1,0.1,0.1,0.3,0.4,0.1,0.1,0.3,0.1,0.8,0.4,0.1,0.1,0.3
0.5,0.6,0.1,0.7,0.2,0.1,0.8,0.6,0.3,0.3,0.3,0.8,0.2,0.3,1.0,0.1,0.1,0.1,0.1,0.6,0.1,0.1,0.6,0.1,0.4,0.6,0.1,0.2,0.3
0.3,0.2,0.9,0.1,0.7,0.3,0.2,0.1,0.1,0.8,0.6,0.1,0.2,0.1,0.1,1.0,0.4,0.8,0.1,0.2,0.2,0.2,0.3,0.1,0.2,0.1,0.3,0.4,0.3
0.5,0.3,0.4,0.3,0.3,0.9,0.6,0.2,0.7,0.2,0.3,0.1,0.3,0.1,0.1,0.4,1.0,0.2,0.3,0.4,0.7,0.8,0.2,0.6,0.1,0.1,0.1,0.8,0.3
0.3,0.2,0.8,0.1,0.7,0.2,0.2,0.1,0.1,0.3,0.3,0.1,0.2,0.1,0.1,0.8,0.2,1.0,0.2,0.3,0.1,0.2,0.3,0.1,0.1,0.1,0.1,0.1,0.3
0.3,0.9,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.1,0.1,0.1,0.4,0.3,0.1,0.1,0.3,0.2,1.0,0.6,0.3,0.2,0.4,0.1,0.3,0.1,0.1,0.1,0.3
0.5,0.7,0.1,0.6,0.1,0.3,0.3,0.5,0.3,0.2,0.1,0.4,0.2,0.4,0.6,0.2,0.4,0.3,0.6,1.0,0.3,0.6,0.4,0.5,0.2,0.1,0.1,0.3,0.3
0.4,0.3,0.4,0.1,0.2,0.4,0.1,0.1,0.6,0.1,0.1,0.1,0.3,0.1,0.1,0.2,0.7,0.1,0.3,0.3,1.0,0.6,0.1,0.5,0.2,0.1,0.3,0.4,0.3
0.1,0.1,0.1,0.2,0.1,0.95,0.3,0.1,0.6,0.1,0.1,0.1,0.5,0.1,0.1,0.2,0.8,0.2,0.2,0.6,0.6,1.0,0.3,0.6,0.1,0.1,0.1,0.6,0.3
0.6,0.6,0.6,0.3,0.3,0.3,0.6,0.6,0.2,0.3,0.3,0.4,0.2,0.3,0.6,0.3,0.2,0.3,0.4,0.4,0.1,0.3,1.0,0.4,0.3,0.3,0.2,0.4,0.3
0.1,0.1,0.1,0.1,0.1,0.5,0.3,0.1,0.3,0.1,0.1,0.1,0.6,0.1,0.1,0.1,0.6,0.1,0.1,0.5,0.5,0.6,0.4,1.0,0.1,0.1,0.1,0.5,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.3,0.1,0.1,0.1,0.5,0.5,0.8,0.4,0.2,0.1,0.1,0.3,0.2,0.2,0.1,0.3,0.1,1.0,0.4,0.1,0.1,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.5,0.3,0.4,0.6,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.3,0.1,0.4,1.0,0.2,0.1,0.3
0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.2,0.1,0.1,0.1,0.2,0.6,0.1,0.1,0.3,0.1,0.1,0.1,0.1,0.3,0.1,0.2,0.1,0.1,0.2,1.0,0.3,0.3
0.1,0.1,0.6,0.5,0.3,0.6,0.7,0.2,0.5,0.3,0.2,0.4,0.2,0.1,0.2,0.4,0.8,0.1,0.1,0.3,0.4,0.6,0.4,0.5,0.1,0.1,0.3,1.0,0.3
0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,1.0"""
    )
    # pylint: enable=line-too-long, single-line-pragma

    def test_validate_default_similarities(self) -> None:
        recommendations_services.validate_topic_similarities(
            recommendations_services.DEFAULT_TOPIC_SIMILARITIES_STRING
        )

    def test_update_topic_similarities(self) -> None:
        recommendations_services.update_topic_similarities(
            'Art,Biology,Chemistry\n'
            '1.0,0.2,0.1\n'
            '0.2,1.0,0.8\n'
            '0.1,0.8,1.0'
        )

        with self.assertRaisesRegex(
            Exception,
            (
                'Length of topic similarities columns: 2 does not match '
                'length of topic list: 3.'
            ),
        ):
            recommendations_services.update_topic_similarities(
                'Art,Biology,Chemistry\n1.0,0.2,0.1\n0.2,1.0,0.8'
            )

        with self.assertRaisesRegex(
            Exception,
            (
                'Length of topic similarities rows: 2 does not match '
                'length of topic list: 3.'
            ),
        ):
            recommendations_services.update_topic_similarities(
                'Art,Biology,Chemistry\n'
                '1.0,0.2,0.1\n'
                '0.2,1.0\n'
                '0.1,0.8,1.0'
            )

        with self.assertRaisesRegex(
            ValueError,
            'Expected similarity to be between 0.0 and 1.0, received 800',
        ):
            recommendations_services.update_topic_similarities(
                'Art,Biology,Chemistry\n'
                '1.0,0.2,0.1\n'
                '0.2,1.0,800\n'
                '0.1,0.8,1.0'
            )

        with self.assertRaisesRegex(
            ValueError, 'Expected similarity to be a float, received string'
        ):
            recommendations_services.update_topic_similarities(
                'Art,Biology,Chemistry\n'
                'string,0.2,0.1\n'
                '0.2,1.0,0.8\n'
                '0.1,0.8,1.0'
            )

        with self.assertRaisesRegex(
            Exception, 'Topic Fake Topic not in list of known topics.'
        ):
            recommendations_services.update_topic_similarities(
                'Fake Topic,Biology,Chemistry\n'
                'string,0.2,0.1\n'
                '0.2,1.0,0.8\n'
                '0.1,0.8,1.0'
            )

        with self.assertRaisesRegex(
            Exception, 'Expected topic similarities to be symmetric.'
        ):
            recommendations_services.update_topic_similarities(
                'Art,Biology,Chemistry\n'
                '1.0,0.2,0.1\n'
                '0.3,1.0,0.8\n'
                '0.8,0.1,1.0'
            )

    def test_get_topic_similarity(self) -> None:
        self.assertEqual(
            recommendations_services.get_topic_similarity('Art', 'Biology'), 0.1
        )
        self.assertEqual(
            recommendations_services.get_topic_similarity('Art', 'Art'),
            feconf.SAME_TOPIC_SIMILARITY,
        )
        self.assertEqual(
            recommendations_services.get_topic_similarity('Topic 1', 'Topic 2'),
            feconf.DEFAULT_TOPIC_SIMILARITY,
        )
        self.assertEqual(
            recommendations_services.get_topic_similarity('Topic', 'Topic'),
            feconf.SAME_TOPIC_SIMILARITY,
        )

        recommendations_services.update_topic_similarities(
            'Art,Biology,Chemistry\n'
            '1.0,0.2,0.1\n'
            '0.2,1.0,0.8\n'
            '0.1,0.8,1.0'
        )
        self.assertEqual(
            recommendations_services.get_topic_similarity('Art', 'Biology'), 0.2
        )

    def test_get_topic_similarities_as_csv(self) -> None:
        # The splitlines() is needed because a carriage return is added in
        # the returned string.
        topic_similarities = (
            recommendations_services.get_topic_similarities_as_csv()
        )

        self.assertEqual(
            topic_similarities.splitlines(),
            self.TOPIC_SIMILARITIES_DEFAULT.splitlines(),
        )

        recommendations_services.update_topic_similarities(
            'Art,Biology,Chemistry\n'
            '1.0,0.2,0.1\n'
            '0.2,1.0,0.8\n'
            '0.1,0.8,1.0'
        )
        topic_similarities = (
            recommendations_services.get_topic_similarities_as_csv()
        )
        self.assertEqual(
            topic_similarities.splitlines(),
            self.TOPIC_SIMILARITIES_UPDATED.splitlines(),
        )


class RecommendationsServicesUnitTests(test_utils.GenericTestBase):
    """Test recommendations services relating to exploration comparison."""

    EXP_DATA: Dict[str, Dict[str, str]] = {
        'exp_id_1': {
            'category': 'Art',
        },
        'exp_id_2': {
            'category': 'Biology',
        },
        'exp_id_3': {
            'category': 'Chemistry',
        },
        'exp_id_4': {
            'category': 'Art',
        },
    }
    USER_DATA: Dict[str, Dict[str, str]] = {
        'alice': {'email': 'alice@example.com'},
        'bob': {'email': 'bob@example.com'},
        'charlie': {'email': 'charlie@example.com'},
    }

    def setUp(self) -> None:
        """Before each individual test, set up dummy explorations and users."""
        super().setUp()

        for name, user in self.USER_DATA.items():
            self.signup(user['email'], name)
            user['id'] = self.get_user_id_from_email(user['email'])
            self.USER_DATA[name]['id'] = user['id']

        self.EXP_DATA['exp_id_1']['owner_id'] = self.USER_DATA['alice']['id']
        self.EXP_DATA['exp_id_2']['owner_id'] = self.USER_DATA['alice']['id']
        self.EXP_DATA['exp_id_3']['owner_id'] = self.USER_DATA['bob']['id']
        self.EXP_DATA['exp_id_4']['owner_id'] = self.USER_DATA['charlie']['id']

        for exp_id, exp in self.EXP_DATA.items():
            self.save_new_valid_exploration(
                exp_id, exp['owner_id'], category=exp['category']
            )
            owner = user_services.get_user_actions_info(exp['owner_id'])
            rights_manager.publish_exploration(owner, exp_id)

    def test_recommendation_categories_and_matrix_headers_match(self) -> None:
        topic_similarities_lines = (
            recommendations_services.DEFAULT_TOPIC_SIMILARITIES_STRING.split(
                '\n'
            )
        )
        matrix_categories = sorted(topic_similarities_lines[0].split(','))
        self.assertEqual(
            matrix_categories,
            sorted(recommendations_services.RECOMMENDATION_CATEGORIES),
        )

    def test_get_item_similarity(self) -> None:
        exp_summaries = exp_services.get_all_exploration_summaries()

        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_1'], exp_summaries['exp_id_2']
            ),
            4.5,
        )
        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_4'], exp_summaries['exp_id_4']
            ),
            9.0,
        )

        system_user = user_services.get_system_user()
        rights_manager.unpublish_exploration(system_user, 'exp_id_2')
        exp_summaries = exp_services.get_all_exploration_summaries()
        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_1'], exp_summaries['exp_id_2']
            ),
            0.0,
        )

    def test_get_item_similarity_when_language_code_differs(self) -> None:
        exp_summaries = exp_services.get_all_exploration_summaries()
        exp_summaries['exp_id_1'].language_code = 'en'
        exp_summaries['exp_id_2'].language_code = 'es'
        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_1'], exp_summaries['exp_id_2']
            ),
            2.5,
        )

    def test_get_item_similarity_when_owner_ids_differs(self) -> None:
        exp_summaries = exp_services.get_all_exploration_summaries()
        exp_summaries['exp_id_1'].owner_ids = ['owner_id_1']
        exp_summaries['exp_id_2'].owner_ids = ['owner_id_2']
        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_1'], exp_summaries['exp_id_2']
            ),
            3.5,
        )

    def test_get_item_similarity_when_time_delta_is_greater_than_7_days(
        self,
    ) -> None:
        exp_summaries = exp_services.get_all_exploration_summaries()
        # Test case where time_delta_days > 7.
        time_in_past = utils.get_current_utc_datetime() - datetime.timedelta(
            days=10
        )
        exp_summaries['exp_id_2'].exploration_model_last_updated = time_in_past
        self.assertEqual(
            recommendations_services.get_item_similarity(
                exp_summaries['exp_id_1'], exp_summaries['exp_id_2']
            ),
            3.5,
        )

    def test_get_and_set_exploration_recommendations(self) -> None:
        recommended_exp_ids = ['exp_id_2', 'exp_id_3']
        recommendations_services.set_exploration_recommendations(
            'exp_id_1', recommended_exp_ids
        )
        saved_recommendation_ids = (
            recommendations_services.get_exploration_recommendations('exp_id_1')
        )
        self.assertEqual(recommended_exp_ids, saved_recommendation_ids)

        recommended_exp_ids = ['exp_id_3']
        recommendations_services.set_exploration_recommendations(
            'exp_id_1', recommended_exp_ids
        )
        saved_recommendation_ids = (
            recommendations_services.get_exploration_recommendations('exp_id_1')
        )
        self.assertEqual(recommended_exp_ids, saved_recommendation_ids)

        saved_recommendation_ids = (
            recommendations_services.get_exploration_recommendations('exp_id_0')
        )
        self.assertEqual(saved_recommendation_ids, [])

    def test_delete_recommendations_for_exploration(self) -> None:
        recommendations_services.delete_explorations_from_recommendations(
            ['exp_id_1', 'exp_id_2']
        )
        self.assertIsNone(
            recommendations_models.ExplorationRecommendationsModel.get_by_id(
                'exp_id_1'
            )
        )
        self.assertIsNone(
            recommendations_models.ExplorationRecommendationsModel.get_by_id(
                'exp_id_2'
            )
        )

    def test_delete_exploration_from_recommendations(self) -> None:
        recommendations_services.set_exploration_recommendations(
            'exp_id_1', ['exp_id_3', 'exp_id_4']
        )
        recommendations_services.set_exploration_recommendations(
            'exp_id_2', ['exp_id_1', 'exp_id_3', 'exp_id_4']
        )

        recommendations_services.delete_explorations_from_recommendations(
            ['exp_id_3', 'exp_id_4']
        )
        recommendations_1 = (
            recommendations_models.ExplorationRecommendationsModel.get_by_id(
                'exp_id_1'
            )
        )
        recommendations_2 = (
            recommendations_models.ExplorationRecommendationsModel.get_by_id(
                'exp_id_2'
            )
        )
        self.assertEqual([], recommendations_1.recommended_exploration_ids)
        self.assertEqual(
            ['exp_id_1'], recommendations_2.recommended_exploration_ids
        )