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import boto3.exceptions
import botocore.exceptions
import pytest
import boto3
from moto import mock_aws
from unittest.mock import patch, MagicMock
from unittest import TestCase
import os
import logging
import json
from src.extract_lambda import (
list_existing_s3_files,
connect_to_database,
DBConnectionException,
lambda_handler,
process_and_upload_tables,
retrieve_secrets,
)
@pytest.fixture(scope="class")
def mock_config():
env_vars = {
"host": "abc",
"port": "5432",
"user": "def",
"password": "password",
"database": "db",
}
with patch(
"src.extract_lambda.retrieve_secrets", 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_SECURITY_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")
@pytest.fixture(scope="class")
def s3_mock_bucket(s3_client):
bucket = s3_client.create_bucket(
Bucket="extract_bucket",
CreateBucketConfiguration={"LocationConstraint": "eu-west-2"},
)
return bucket
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_mock_bucket):
list_existing_s3_files("extract_bucket", client=s3_client)
assert "The bucket is empty" in caplog.text
def test_retrieves_file_content(self, s3_client, caplog, s3_mock_bucket):
s3_client.upload_file("tests/dummy.txt", "extract_bucket", "dummy.txt")
result = list_existing_s3_files("extract_bucket", client=s3_client)
assert list(result.values()) == ["This is a test file."]
class TestConnectToDatabase:
# had mock_config in param
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): # had mock_config in param
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, s3_client, caplog):
caplog.set_level(logging.INFO)
# Mock return values for database queries
queries = [
"SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE';",
"SELECT * FROM Fruits WHERE last_updated > :latest;",
"SELECT column_name FROM INFORMATION_SCHEMA.COLUMNS where table_name = 'Fruits';",
]
return_values = [
[["Fruits"]],
[], # No new rows with a more recent last_updated timestamp
[["Food_type"], ["Flavour"], ["Colour"], ["last_updated"]],
]
vals = dict(zip(queries, return_values))
# Patch the database connection and set return values for queries
with patch("src.extract_lambda.Connection") as mock_db:
mock_db().run.side_effect = return_values
s3_key = "Fruits/2024/08/15/Fruits_16:46:30.csv"
existing_files = {
s3_key: "Food_type,Flavour,Colour,last_updated\nVegetable,Sour,Green,2022-11-03 14:20:49.962\nBerry,Sweet,Red,2022-11-03 14:20:49.962"
}
# Simulate S3 bucket and file setup
s3_client.create_bucket(
Bucket="test_extract_bucket",
CreateBucketConfiguration={"LocationConstraint": "eu-west-2"},
)
s3_client.upload_file(
"tests/dummy_identical.csv", "test_extract_bucket", s3_key
)
# Run the process_and_upload_tables function
process_and_upload_tables(mock_db(), existing_files, client=s3_client)
# Assert that the log contains "No new data"
assert "No new data" in caplog.text
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