An example of BDD-influenced use of JUnit

StackTest.java

import org.junit.Test;

import java.util.EmptyStackException;
import java.util.Stack;

import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertThat;

public class StackTest {
    Stack<String> stack = new Stack<String>();

    @Test public void
    isInitiallyEmpty() {
        assertThat(stack.isEmpty(), is(true));
    }

    @Test(expected=EmptyStackException.class) public void
    refusesToPopWhenItIsEmpty() {
        stack.pop();
    }

    @Test public void
    isNotEmptyWhenItHasAnItem() {
        stack.push("an item");
        assertThat(stack.isEmpty(), is(false));
    }

    @Test public void
    popsAnItem() {
        stack.push("first item");

        String poppedItem = stack.pop();
        assertThat(poppedItem, is("first item"));
    }

    @Test public void
    removesAnItemWhenItIsPopped() {
        stack.push("first item");

        stack.pop();
        assertThat(stack.isEmpty(), is(true));
    }
}