You’re a Java developer for a large company that sells stock photography. You’re responsible for the service that ingests images, and a recent database change has broken the service, despite successful unit testing. Working in IntelliJ IDEA, you’ll build an integration test that replicates the problem, find the cause, fix the problem, and build the infrastructure to develop more integration tests in the future.

Create an alarm system that warns you before your system breaks. You’re a Java developer for a large company that sells stock photography. You’re responsible for the service that ingests images. A recent upgrade to the image scaling library has caused a problem with the aspect ratio of thumbnail images. Working in IntelliJ IDEA, you’ll build a layer of integration tests that replicates the problem and also tests assumptions that your unit tests rely on. When you’re done, you’ll have an alarm system that warns you when the assumptions your unit tests rely on are no longer valid, preventing problems in the future.

Ensure your system can accommodate even unstable dependency services. You’re a Java developer for a large company that sells stock photography. You’re responsible for the service that ingests images. Unfortunately, the ingestion process is being negatively affected by a flaky external web service that the ingestion engine uses, and the problem is not reproducible in unit testing since there’s no connection to the external service at that time. Working in IntelliJ IDEA, you’ll establish an in-memory HTTP service, configure it to simulate a dependency service, write a test to reproduce the error, and use the test to build robustness into your system.

You’re a Java developer for a large company that sells stock photography. You’re responsible for the service that ingests images, and this service depends on another subservice: the pricing microservice. As proven by their individual unit tests, each service works as specified. But when the services are combined, new customers are being locked into one pricing table—even those that should have access to pricing that fluctuates depending on factors like promotions, flash sales, and price-tuning. Working in IntelliJ IDEA, you’ll solve this problem by writing an integration test that connects and runs the two services together, allowing you to reproduce the problem locally.