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import pytest
import boto3
from moto import mock_aws
from unittest.mock import patch, MagicMock
from unittest import TestCase
from src.extract_lambda import list_existing_s3_files, connect_to_database, DBConnectionException, lambda_handler, process_and_upload_tables
import os
import logging
import json
@pytest.fixture(scope='class')
def mock_config():
env_vars = {
"host": "abc",
"port": "5432",
"user": "def",
"password": "password",
"database": "db",
}
with patch("src.extract_lambda.get_config", return_value=env_vars) as mock_config:
yield mock_config
@pytest.fixture(scope='class')
def aws_credentials():
os.environ["AWS_ACCESS_KEY_ID"] = 'testing'
os.environ["AWS_SECRET_ACCESS_KEY"] = 'testing'
os.environ["AWS_SECURIT_TOKEN"] = 'testing'
os.environ["AWS_SESSION_TOKEN"] = 'testing'
os.environ["AWS_DEFAULT_REGION"]= 'eu-west-2'
@pytest.fixture(scope='class')
def s3_client(aws_credentials):
with mock_aws():
yield boto3.client('s3')
class TestLambdaHandler:
def test_lambda_handler_files_processed_and_uploaded_successfully(self, mocker):
mock_db = MagicMock()
mock_db.run.side_effect = [
[['Fruits']],
[['Vegetable', 'Sour', 'Green'], ['Berry', 'Sweet', 'Red']],
[['Food_type'], ['Flavour'], ['Colour']]
]
mock_db.columns.return_value = [{'name': 'Food_type'}, {'name': 'Flavour'}, {'name': 'Colour'}]
with patch("src.extract_lambda.connect_to_database", return_value=mock_db):
mock_process_and_upload_tables = mocker.patch("src.extract_lambda.process_and_upload_tables", return_value=mock_db)
mock_list_existing_s3_files = mocker.patch("src.extract_lambda.list_existing_s3_files", return_value={})
event = {}
context = {}
response = lambda_handler(event, context)
assert response['statusCode'] == 200
assert json.loads(response['body']) == 'CSV files processed and uploaded successfully.'
mock_list_existing_s3_files.assert_called_once()
mock_process_and_upload_tables.assert_called_once_with(mock_db, {})
mock_db.close.assert_called_once()
def test_lambda_handler_no_changes_detected_no_files_uploaded(self, mocker):
mock_db = MagicMock()
mock_db.run.side_effect = [
[['Fruits']],
[['Vegetable', 'Sour', 'Green'], ['Berry', 'Sweet', 'Red']],
[['Food_type'], ['Flavour'], ['Colour']]
]
mock_db.columns.return_value = [{'name': 'Food_type'}, {'name': 'Flavour'}, {'name': 'Colour'}]
with patch("src.extract_lambda.connect_to_database", return_value=mock_db):
mock_process_and_upload_tables = mocker.patch("src.extract_lambda.process_and_upload_tables", return_value=False)
mock_list_existing_s3_files = mocker.patch("src.extract_lambda.list_existing_s3_files", return_value={})
event = {}
context = {}
response = lambda_handler(event, context)
assert response['statusCode'] == 200
assert json.loads(response['body']) == 'No changes detected, no CSV files were uploaded.'
mock_list_existing_s3_files.assert_called_once()
mock_process_and_upload_tables.assert_called_once_with(mock_db, {})
mock_db.close.assert_called_once()
def test_lambda_handler_exception_error(self, mocker):
with patch("src.extract_lambda.connect_to_database", side_effect=Exception("Database connection error")):
mock_process_and_upload_tables = mocker.patch("src.extract_lambda.process_and_upload_tables")
mock_list_existing_s3_files = mocker.patch("src.extract_lambda.list_existing_s3_files")
event = {}
context = {}
response = lambda_handler(event, context)
assert response['statusCode'] == 500
assert json.loads(response['body']) == 'Internal server error.'
mock_list_existing_s3_files.assert_not_called()
mock_process_and_upload_tables.assert_not_called()
class TestListExistingS3Files:
def test_error_if_no_bucket(self, s3_client, caplog):
logger = logging.getLogger()
logger.info('Testing now.')
caplog.set_level(logging.ERROR)
list_existing_s3_files(client=s3_client)
assert 'Error listing S3 objects' in caplog.text
def test_error_if_bucket_is_empty(self, s3_client, caplog):
s3_client.create_bucket(Bucket='extract_bucket',
CreateBucketConfiguration={
'LocationConstraint': 'eu-west-2'
})
list_existing_s3_files(client=s3_client)
assert 'The bucket is empty' in caplog.text
def test_error_retrieving_object(self, s3_client, caplog):
s3_client.upload_file('tests/dummy.txt', 'extract_bucket', 'dummy.txt')
list_existing_s3_files(bucket_name='test_bucket', client=s3_client)
assert 'Error retrieving S3 object ' in caplog.text
def test_retrieves_file_content(self, s3_client, caplog):
result = list_existing_s3_files(client=s3_client)
assert list(result.values()) == ['This is a test file.']
class TestConnectToDatabase:
def test_connect_to_database(mock_conn, mock_config):
with patch("src.extract_lambda.Connection", autospec=True) as mock_conn:
connect_to_database()
mock_conn.assert_called_with(
host="abc", user="def", port="5432", password="password", database="db"
)
def test_database_error(self, mock_config):
with pytest.raises(DBConnectionException):
connect_to_database()
def test_logs_interface_error(self, caplog):
logger = logging.getLogger()
logger.info('Testing now.')
caplog.set_level(logging.ERROR)
with pytest.raises(DBConnectionException):
connect_to_database()
assert 'Interface error' in caplog.text
'''
class TestProcessAndUploadTables:
def test_error_process_and_upload_tables(mock_conn, mock_config, s3_client, caplog):
logger = logging.getLogger()
logger.info('Testing now.')
caplog.set_level(logging.ERROR)
####
queries = ["SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE';",
"SELECT * FROM Fruits;",
"SELECT column_name FROM INFORMATION_SCHEMA.COLUMNS where table_name = 'Fruits'"]
return_values = [[['Fruits']],
[['Vegetable','Sour','Green'],['Berry','Sweet','Red']],
[['Food_type'],['Flavour'],['Colour']]]
vals = dict(zip(queries,return_values))
####
with patch('src.extract_lambda.connect_to_database') as mock_db:
mock_db().run.side_effects = return_values
s3_key = 'Fruits/2024/08/15/Fruits_16:46:30.csv'
existing_files = {s3_key: 'Food_type,Flavour,Colour\nFruit,Sour,Green\nBerry,Sweet,Red'}
s3_client.create_bucket(Bucket='extract_bucket',
CreateBucketConfiguration={'LocationConstraint': 'eu-west-2'})
s3_client.upload_file('tests/dummy_identical.csv', 'extract_bucket', s3_key)
process_and_upload_tables(mock_db(), existing_files, client=s3_client)
assert 'No new data.' in caplog.text
'''
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