Developed a shadow-based enhancement for the SubscriptionManager API in the robolectric/robolectric repository, enabling static mapping of slot IDs to subscription IDs to improve cross-SDK compatibility and test reliability. Leveraged Java and Android development skills to implement static ActiveSubscriptionInfo exposure, supporting static API calls and reducing test flakiness caused by dynamic subscription states. Added comprehensive unit tests for getSubId, getSubscriptionIds, and getSubscriptionId across multiple Android SDK versions, ensuring consistent behavior in Robolectric-based testing environments. This work strengthened test quality and developer confidence by enabling reliable, static subscription-related functionality and facilitating robust end-to-end testing for Android applications.