Some microservices are difficult to test because their behavior depends on a long tail of inputs that are hard to model by hand. This post focuses on how to build a repeatable Apache Spark replay harness for testing without creating a second implementation of the service.

• Best Practices
• Engineering
• Testing

Some microservices are difficult to test because their behavior depends on a long tail of inputs that are hard to model by hand. For that class of problem, Apache Spark's massive parallelism and linear scalability can be leveraged to build a regression test harness. That makes it possible to compare old and new implementations, model upcoming rule changes, and quantify impact before a change reaches production.

• Best Practices
• Engineering
• Testing