Using JBehave with Groovy

// require(url:'http://jbehave.org/', jar='jbehave-1.0.1.jar')
import org.jbehave.core.Run
import org.jbehave.core.behaviour.Behaviours

class AlmostEmptyFixedStackBehavior {
    private stack

    void setUp() {
        stack = new FixedStack()
        stack.push 'anything'
        assert !stack.isEmpty()
    }

    void shouldRemainNotEmptyAfterPeek() {
        stack.peek()
        assert !stack.isEmpty()
    }

    void shouldBecomeEmptyAfterPop() {
        stack.pop()
        assert stack.isEmpty()
    }
}

class AlmostFullFixedStackBehavior {
    private stack

    void setUp() {
        stack = new FixedStack()
        (1..<FixedStack.MAXSIZE).each{ x -> stack.push x }
        assert !stack.isFull()
    }

    void shouldBecomeFullAfterPush() {
        stack.push 'anything'
        assert stack.isFull()
    }
}

class EmptyFixedStackBehavior extends GroovyTestCase {
    private stack = new FixedStack()

    void shouldInitiallyBeEmpty() {
        assert stack.isEmpty()
    }

    void shouldNoLongerBeEmptyAfterPush() {
        stack.push 'anything'
        assert !stack.isEmpty()
    }

    void shouldComplainWhenSentPeek() {
        shouldFail(StackUnderflowException) {
            stack.peek()
        }
    }

    void shouldComplainWhenSentPop() {
        shouldFail(StackUnderflowException) {
            stack.pop()
        }
    }
}

class FullFixedStackBehavior extends GroovyTestCase {
    private stack

    void setUp() {
        stack = new FixedStack()
        (1..FixedStack.MAXSIZE).each{ x -> stack.push x }
        assert stack.isFull()
    }

    void shouldRemainFullAfterPeek() {
        stack.peek()
        assert stack.isFull()
    }

    void shouldNoLongerBeFullAfterPop() {
        stack.pop()
        assert !stack.isFull()
    }

    void shouldComplainOnPush() {
        shouldFail(StackOverflowException) {
            stack.push 'anything'
        }
    }
}

class NonEmptyFixedStackBehavior {
    private stack

    void setUp() {
        stack = new FixedStack()
        ('a'..'c').each{ x -> stack.push x }
        assert !stack.isEmpty()
    }

    void shouldAddToTheTopWhenSentPush() {
        stack.push 'd'
        assert stack.peek() == 'd'
    }

    void shouldBeUnchangedWhenSentPushThenPop() {
        stack.push 'anything'
        stack.pop()
        assert stack.peek() == 'c'
    }

    void shouldReturnTheTopItemWhenSentPeek() {
        assert stack.peek() == 'c'
    }

    void shouldNotRemoveTheTopItemWhenSentPeek() {
        assert stack.peek() == 'c'
        assert stack.peek() == 'c'
    }

    void shouldReturnTheTopItemWhenSentPop() {
        assert stack.pop() == 'c'
    }

    void shouldRemoveTheTopItemWhenSentPop() {
        assert stack.pop() == 'c'
        assert stack.pop() == 'b'
    }
}

class AllBehaviours implements Behaviours {
    Class[] getBehaviours() {
        return [
            AlmostEmptyFixedStackBehavior,
            AlmostFullFixedStackBehavior,
            EmptyFixedStackBehavior,
            FullFixedStackBehavior,
            NonEmptyFixedStackBehavior
        ]
    }
}

Run.main('AllBehaviours')