Project build/run dependencies:maven 3 (tested with Apache Maven 3.5.2) and java 8
Build project with :
mvn package site
After successful build run game:
java -jar target/puzzle-game-1.0.jar
After successful build open unit test + code coverage reports in your browser:
target/site/index.html
To check if project has at least 90% code coverage run:
mvn verify
Generated random game board is solvable. Proof of fact:
The initial (solved) state is solvable.
After applying some number of random legal moves it becomes shuffled.
You can solve board at least by repeating inversed previously applied random moves.