src/test/java/au/id/zancanaro/javacheck/state/queue/commands/Poll.java


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package au.id.zancanaro.javacheck.state.queue.commands;

import au.id.zancanaro.javacheck.state.Command;
import au.id.zancanaro.javacheck.state.CommandValue;
import au.id.zancanaro.javacheck.state.queue.QueueState;

import java.util.ArrayList;
import java.util.List;

import static org.junit.Assert.assertEquals;

public class Poll<T> extends Command<QueueState<T>, Void, T> {
    @Override
    public boolean preCondition(QueueState<T> state, Void args) {
        return state != null && !state.getAbstractQueue().isEmpty();
    }

    @Override
    public T runCommand(QueueState<T> state, Void args) {
        return state.getConcreteQueue().poll();
    }

    @Override
    public QueueState<T> nextState(QueueState<T> state, Void args, CommandValue<T> result) {
        List<T> newState = new ArrayList<>(state.getAbstractQueue());
        newState.remove(0);
        return state.withAbstractQueue(newState);
    }

    @Override
    public void postCondition(QueueState<T> oldState, QueueState<T> newState, Void args, T result) {
        assertEquals(oldState.getAbstractQueue().get(0), result);
    }
}