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Diffstat (limited to 'tests/test_extract_lambda.py')
| -rw-r--r-- | tests/test_extract_lambda.py | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/tests/test_extract_lambda.py b/tests/test_extract_lambda.py new file mode 100644 index 0000000..548ce67 --- /dev/null +++ b/tests/test_extract_lambda.py @@ -0,0 +1,247 @@ +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, + extract_bucket, +) + + +@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_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={ + "updated": ["Fruits"], + "no change": ["Vegetable", "Berry"], + }, + ) + 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 for Fruits and uploaded successfully." + "The following tables were not updated: Vegetable, Berry" + ) + 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_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={"updated": [], "no change": ["Fruits"]}, + ) + 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_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 TestExtractBucket: + def test_extract_bucket_returns_bucket_name(self, s3_client, s3_mock_bucket): + result = extract_bucket(s3_client) + assert result == "extract_bucket" + + def test_bucket_returns_first_bucket(self, s3_client): + bucket1 = s3_client.create_bucket( + Bucket="bucket1", + CreateBucketConfiguration={"LocationConstraint": "eu-west-2"}, + ) + result = extract_bucket(s3_client) + assert result == "extract_bucket" + + def test_returns_index_error_if_no_buckets(self, s3_client): + s3_client.delete_bucket(Bucket="extract_bucket") + s3_client.delete_bucket(Bucket="bucket1") + + with pytest.raises(IndexError, match="list index out of range"): + extract_bucket(s3_client) + + +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: + 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(self, 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 |