What to do before the interview

• Check out the codebase and get familiar how it works such as
  • Google protobuf https://developers.google.com/protocol-buffers
• Set up your local development environment
  • Java 17
  • IDE of your preference such as
    • Intellij Community Edition or
    • Visual Studio Code with Extension Pack for Java
    • Make sure you can put breakpoints and debug the code using IDE which would help massively, especially for the UAT project

Useful maven commands

• ./mvnw clean compile to regenerate code from protobuf definitions and compile the code
• ./mvnw test to run all the tests

Task (To be completed during the interview, do not attempt beforehand)

Tic-tac-toe or Xs and Os, is a paper-and-pencil game for two players, X and O, who take turns marking spaces in a 3×3 grid.

The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row wins the game.

Follow the provided hello world rpc process and its UAT test example (com.gs.interviews.uat.rpcapi.handlers.HelloWorldUAT), implement tests to play the Tic-tac-toe game.

The following tasks need to be completed in order for the game to be functional:

1. A player can create a new Tic-tac-toe game
2. The second player can join the existing game
3. Each player can place their X or O in turn
4. Each player can query the game result: WaitMoreJoin, Ongoing, Win, Draw, Lose