Software testing is essential to ensure that information systems function according to their specifications. The BMKG Pasuruan Digital Library was developed as a solution for managing internship and thesis documents, yet requires a comprehensive evaluation to guarantee optimal performance. This study applies the Black Box Testing method using Equivalence Partitioning (EP) and Use Case Testing (UCT) techniques to examine the system’s functionality. EP validates input by dividing it into valid and invalid classes, while UCT evaluates real user scenarios such as searching, sorting, uploading, and downloading documents for both users and administrators. A total of 47 test cases were executed, resulting in 46 valid and 1 invalid case related to email input validation. The testing achieved a 97.87% success rate, indicating that the system functions effectively according to its specifications, though improvements are needed in the email validation mechanism.