Operational testing

Run the existing application test suite with:

./mvnw test

The suite includes five controller tests using data/test_1.jpeg through data/test_5.jpeg. They build an in-memory answers CSV, submit an image multipart part, assert HTTP 200, assert 40 total questions, and compare the correct count with fixture ground truth. ImageProcessingServiceTest separately checks OMR extraction for all five files and includes a focused extraction test for test_3.jpeg.

The tests prove behavior for the checked-in fixtures and the test OCR double. They do not prove production Tesseract accuracy, arbitrary sheet layouts, upload-limit behavior, authentication, concurrency, or long-running debug-file management.

Test runs can create timestamped overlay JPEGs under data/debug/. Review that output as test data and do not publish it without checking its contents.