A fully functional in-memory implementation of Android's SharedPreferences interface for unit testing. Supports listeners, type checking (throws ClassCastException on mismatch), and real read-after-write semantics. Can be extracted and reused in any Android project to replace SharedPreferences in tests without mocking frameworks.

A set of Kotlin property delegates (BooleanPreference, IntPreference, StringPreference, etc.) that provide type-safe access to SharedPreferences. Each delegate handles default values, commit vs apply, and can be observed via a callback. This pattern is cleanly isolated and can be extracted as a small library for any Android project using SharedPreferences.

A jsdom-based test harness for WebView-injected JavaScript assets. It creates a mock androidApp bridge (with controllable getTranslation responses), sets up IntersectionObserver stubs, and provides a reusable setup for testing DOM manipulation scripts. This pattern is directly applicable to any project that injects JavaScript into WebView and needs to test it in a Node.js environment.

A standalone, read-only PDF parser written in pure Kotlin. It handles classic and cross-reference streams, object streams, FlateDecode with PNG predictors, and builds a COS object model. No external PDF libraries are used. This component demonstrates deep understanding of the PDF specification and can be extracted as a lightweight PDF parsing library for Android or JVM projects.