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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_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("extract_bucket", 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, 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']]] # why are individual column names in lists
vals = dict(zip(queries,return_values))
# {"SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE';": [['Fruits']], 'SELECT * FROM Fruits;': [['Vegetable', 'Sour', 'Green'], ['Berry', 'Sweet', 'Red']], "SELECT column_name FROM INFORMATION_SCHEMA.COLUMNS where table_name = 'Fruits'": [['Food_type'], ['Flavour'], ['Colour']]}
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\nFruit,Sour,Green\nBerry,Sweet,Red'}
s3_client.create_bucket(Bucket='test_extract_bucket',
CreateBucketConfiguration={'LocationConstraint': 'eu-west-2'})
print(s3_client.list_buckets)
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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