This curriculum spans the breadth of a multi-workshop technical enablement program, addressing the same data validation, pipeline integrity, and compliance rigor found in enterprise data platform migrations and large-scale cloud data lake rollouts.
Module 1: Defining Big Data Testing Scope and Objectives
- Determine data source diversity (structured, semi-structured, unstructured) and ingestion frequency to align test coverage with pipeline architecture.
- Select key data domains for testing based on business criticality, regulatory exposure, and downstream consumption patterns.
- Establish data quality benchmarks (completeness, accuracy, consistency, timeliness) in collaboration with data stewards and business SMEs.
- Define test objectives for batch versus streaming pipelines, including latency thresholds and checkpoint recovery expectations.
- Map data lineage from source to target to identify high-risk transformation points requiring validation.
- Decide whether to include performance and scalability testing within the scope based on SLA commitments and infrastructure constraints.
- Assess the need for synthetic data generation when production data is restricted due to privacy or volume constraints.
- Document assumptions about source system stability and schema evolution to guide test design and exception handling.
Module 2: Test Environment Architecture and Data Provisioning
- Configure isolated Hadoop or cloud-based test clusters that mirror production topology, including storage, compute, and network segmentation.
- Implement data masking or anonymization for sensitive fields when replicating production datasets to non-production environments.
- Design data subset extraction strategies that preserve referential integrity and statistical representativeness for testing.
- Automate environment provisioning using infrastructure-as-code (IaC) tools to ensure consistency across test cycles.
- Integrate test data management tools with orchestration platforms (e.g., Airflow, Oozie) to synchronize data availability with job schedules.
- Handle schema drift by versioning test datasets and aligning them with ETL job versions under test.
- Configure cross-account or cross-VPC access for cloud-based data lakes to enable secure data movement into test environments.
- Validate data freshness and synchronization windows between source replicas and test data stores.
Module 3: Data Quality and Validation Techniques
- Implement rule-based validation using tools like Great Expectations or custom Spark jobs to check for nulls, duplicates, and format compliance.
- Compare record counts and aggregate metrics (sums, averages) between source and target systems to detect data loss or duplication.
- Validate complex JSON or Avro schema fields by parsing and asserting path-level constraints in transformation outputs.
- Use probabilistic matching to verify referential integrity when primary keys are obfuscated or transformed.
- Design delta validation logic to test incremental data loads, ensuring only new or changed records are processed.
- Implement data reconciliation workflows for distributed systems where eventual consistency affects validation timing.
- Log validation failures with context (job ID, timestamp, data sample) to facilitate root cause analysis.
- Integrate data quality rules into CI/CD pipelines to block deployment of flawed transformation logic.
Module 4: Performance and Scalability Testing
- Design load tests that simulate peak data ingestion rates using tools like Kafka Producer performance scripts or Spark stress jobs.
- Measure end-to-end latency from source capture to target availability under increasing data volumes.
- Identify bottlenecks in resource allocation (YARN queues, Spark executors, memory overhead) during high-load scenarios.
- Test horizontal scaling behavior by increasing cluster nodes and measuring throughput improvements.
- Validate checkpointing and recovery mechanisms in streaming jobs after simulated node failures.
- Compare compression formats (Parquet, ORC, Snappy) for impact on I/O performance and storage utilization.
- Monitor garbage collection and JVM overhead in long-running streaming applications to detect memory leaks.
- Establish baseline performance metrics for regression tracking across deployment cycles.
Module 5: Testing Data Transformation and ETL Logic
- Validate complex Spark SQL or PySpark transformations by comparing intermediate and final outputs against expected results.
- Test error handling in ETL jobs by injecting malformed records and verifying proper routing to dead-letter queues.
- Verify type casting and date/time zone conversion logic across heterogeneous source systems.
- Check for data truncation or precision loss during numeric or string transformations in pipeline stages.
- Test conditional branching logic in workflows (e.g., Airflow DAGs) based on data thresholds or control file triggers.
- Validate slowly changing dimension (SCD) logic in data warehouse loads, including Type 1 and Type 2 handling.
- Ensure idempotency of transformation jobs to prevent unintended side effects during reprocessing.
- Trace business rule implementations from requirements documents to actual code and test assertions.
Module 6: Metadata and Lineage Testing
- Verify metadata extraction from source systems (e.g., Hive metastore, AWS Glue Catalog) matches documented schema definitions.
- Test lineage tracking tools (e.g., Apache Atlas, DataHub) to confirm accurate mapping of data flow across transformations.
- Validate timestamps and job identifiers in audit tables to ensure traceability of data modifications.
- Check that data provenance tags (source system, ingestion time, job version) are preserved across pipeline stages.
- Test metadata search and impact analysis functions to support compliance and change management processes.
- Ensure custom metadata annotations (e.g., PII flags, sensitivity labels) propagate correctly through transformations.
- Validate schema evolution handling in metadata systems when new fields are added or deprecated.
- Automate metadata consistency checks as part of regression test suites.
Module 7: Security and Compliance Testing
- Test role-based access controls (RBAC) in data lakes to ensure users and services can only access authorized datasets.
- Validate encryption at rest and in transit for data stored in HDFS, S3, or ADLS.
- Verify masking or redaction of PII/PHI fields in test outputs using pattern detection and content scanning tools.
- Test audit logging mechanisms to confirm all data access and modification events are captured with user context.
- Conduct vulnerability scans on cluster nodes and services (e.g., HiveServer2, Spark History Server) to identify exposure.
- Validate data retention and purge logic to ensure compliance with GDPR, CCPA, or industry-specific regulations.
- Test secure credential handling in jobs (e.g., via HashiCorp Vault or cloud KMS) to prevent hardcoding in scripts.
- Assess segregation of duties in test environment access to prevent unauthorized production data manipulation.
Module 8: Test Automation and CI/CD Integration
- Develop reusable test frameworks using PyTest or ScalaTest to validate Spark and Flink jobs in isolated contexts.
- Integrate data validation scripts into CI pipelines to execute on pull requests for ETL code changes.
- Configure test orchestration to run data quality checks in parallel with performance and functional tests.
- Use containerization (Docker, Kubernetes) to standardize test execution environments across development and QA.
- Implement test result aggregation and reporting using tools like JUnit XML or custom dashboards in Grafana.
- Manage test data versioning alongside code in Git to enable reproducible test runs.
- Design retry and timeout logic for flaky integration tests involving external data sources or APIs.
- Enforce test coverage thresholds to prevent merging of code with insufficient validation.
Module 9: Monitoring, Reporting, and Defect Management
- Deploy real-time monitoring for data pipeline health using Prometheus and custom metrics from Spark applications.
- Configure alerting thresholds for data latency, job failures, and data quality rule violations.
- Integrate test outcomes with incident management systems (e.g., Jira, ServiceNow) for defect tracking.
- Generate executive-level reports summarizing data quality trends, test coverage, and SLA adherence.
- Classify defects by severity (critical data loss, minor formatting issue) to prioritize remediation efforts.
- Conduct root cause analysis for recurring data issues using logs, metrics, and pipeline telemetry.
- Maintain a data defect knowledge base to improve test case design and prevent regression.
- Coordinate with DevOps and SRE teams to align data testing alerts with overall system observability practices.