Mastering ELT Testing with Python and Databricks

Learning Objectives

Understand core ELT testing principles and their application in a business context.

Identify common failure points in data pipelines and articulate the business impact of bad data.

Differentiate between various testing types (Functional, Data Quality, Integration, etc.) and select appropriate approaches for different scenarios.

Design and interpret test cases, including those for business rule validation and data transformations.

Apply basic Python programming skills for writing and understanding test scripts.

Comprehend and test JSON data structures, including parsing and schema validation, Utilize PySpark for basic CSV data reading and validation tasks, and Understanding the fundamentals of SQL testing for data verification.

Recognize the purpose and basic application of Pytest for test automation, including fixtures and parameterization.

Appreciate the importance of testing concepts like idempotence, boundary value analysis, and dependency management in ELT pipelines.

Overview

NovaMart Global Commerce is a leading e-commerce powerhouse, revolutionizing how customers shop online by offering a vast selection of products, from cutting-edge electronics and fashion to everyday essentials and groceries. With millions of transactions processed daily and a rapidly expanding global customer base, NovaMart's success hinges on data-driven insights derived from its sophisticated ELT (Extract, Load, Transform) pipelines.

At the heart of NovaMart's operations, these pipelines ingest, process, and analyze massive volumes of data from diverse sources, including:

Sales & Order Systems: Capturing every customer purchase, return, and interaction.
Supplier & Inventory Feeds: Managing product catalogs, stock levels, and supply chain logistics.
Customer Relationship Management (CRM): Storing customer profiles, preferences, and interaction history.
Website & App Analytics: Tracking user behavior, clickstreams, and engagement patterns.
Marketing & Campaign Platforms: Measuring the effectiveness of promotional activities.

Core Operations at NovaMart Driven by Data:

Personalized Customer Experience: Tailoring product recommendations, offers, and content based on browsing history and purchase patterns.
Dynamic Inventory Management: Optimizing stock levels across global warehouses to meet demand and minimize holding costs.
Strategic Pricing & Promotions: Adjusting prices and launching targeted campaigns based on market trends and competitor analysis.
Financial Reporting & Compliance: Ensuring accurate and timely financial statements, sales tax calculations, and regulatory adherence.
Logistics & Fulfillment Optimization: Streamlining an order processing, shipping, and delivery to enhance customer satisfaction.

As an ELT Test Engineer at NovaMart, you play a pivotal role. Your expertise ensures that the data fueling these critical operations is accurate, complete, consistent, and reliable. Errors in the ELT pipelines can lead to incorrect inventory levels, miscalculated financial reports, ineffective marketing spend, and a compromised customer experience. Your diligence in testing is what safeguards NovaMart's reputation and its bottom line. This assessment will gauge your understanding of the fundamental testing principles and practices essential for maintaining the integrity of NovaMart's data ecosystem.

Prerequisites

Familiarity with basic Python syntax (variables, data types, lists, dictionaries, loops, conditional statements, functions).
Conceptual understanding of ETL/ELT processes and data pipelines.
Basic knowledge of data formats like JSON and CSV.
Exposure to fundamental SQL query concepts.
Successful completion of the Databricks ELT Testing Program modules covering the topics listed in the Learning Objectives.