The workshop focuses specifically on test-driven development mantra and provides tips and tricks on how to achieve that. After the workshop you will be able to practice test-driven development with any language, it is not limited to Java.

• 15' Min intro
• 30' live hacking by the presenter
• 45' Involving the audience, we do it together
• 45' The audience works on their own and present the solution to the rest

We do 10' breaks between the blocks.

Do the following steps before the workshop!

• Import MoveIt_step0 in your IDE as a Gradle project and build it, Java 8 should be sufficient.
• Run the application, you can move a square with WASD keys on the screen.
• Make sure the dummy test is working!

We will program a turn-based mini-game with undo and redo. In the end, you can move around on an xz-plane and you can undo and redo the movements of your character. For this, we implement the command pattern from the gang of 4. See here if you want to read more about this pattern.

We will capsulate every movement into a command in our case the MoveCommand, we do not reuse command objects. The command has two methods an execute() and an undo()

We store these commands into a history object. The History class does have execute(Command command), undo(), and redo() methods.

The history object contains a list of commands and in this example the last executed command was command2

command1 *command2*

To execute a command we simply call history.execute(command) that then calls command.exectue() and store the command into a structure. We were initially on command2 and move on to command3

command1 command2 *command3*

To undo the current command, we simply call history.undo() that calls then command.undo() of command3 and move to the command before in our example to command2

command1 *command2* command3

To redo a command we undid we simply move one command further and call again command.execute() in our example it is command3

command1 command2 *command3*