StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
19108754
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2013-10-01T05:39:08.160
FavoriteCount
0
LastActivityDate
2013-10-01T05:39:08.160
LastEditDate
LastEditorUserId
0
OwnerUserId
800788
ParentId
19038102
PostTypeId
2
Score
2
ViewCount
0
LastEditorDisplayName
text
Body
While this kind of exercise is worthwhile from the perspective of learning the ins and outs of Java, I would advise caution before applying this to other problems. It's encouraged to use JUnit to exercise the public interface of your class under test. In the case of <code>ArrayStack</code>, let's assume it has a few methods: <blockquote> <ul> <li><code>void push(Object o)</code></li> <li><code>Object pop()</code></li> <li><code>void clear()</code></li> </ul> </blockquote> @dkaztzel suggested one solution - to implement a package private method to defensively copy the contents of your internal stack. Let's say it looks like this: <pre><code>Object[] getStack() { return stack.clone(); } </code></pre> Assuming you've implemented a few unit tests to verify that <code>push</code> and <code>pop</code> are working as intended (including the edge cases of empty and full stacks), then you would create a unit test as follows: <pre><code>@Test public void probablyNotAGoodTest() { ArrayStack arrayStack = new ArrayStack(); arrayStack.push("Luke"); arrayStack.clear(); Object[] stackCopy = arrayStack.getStack(); assertNull(stackCopy[0]); } </code></pre> This achieves your intent of verifying that in fact you've set the value at the index to null once an element has been popped. I'm always a little suspicious when I have to write production code whose sole purpose is to help me test my contract. Not to say that this approach is wrong, but that it requires careful consideration. Here the requirement is to ensure that popped objects are actually removed from the internal stack, so maybe this is okay. Another approach would be to enrich the <code>ArrayStack</code> interface, and provide a method to retrieve a particular object at a given index. This method could throw an exception if a null object is encountered, and then you could test for that. Here's what the method and a test could look like (please do some additional verification before you use this): <pre><code>public Object getObjectAtIndex(int i) { if (i >= maxSize) { throw new IllegalArgumentException(); } if (stack[i] == null) { throw new NullPointerException(); } return stack[i]; } </code></pre> And then the test: <pre><code>@Test(expected=NullPointerException.class) public void tryToGetAClearedObject() { ArrayStack arrayStack = new ArrayStack(); arrayStack.push("Luke"); arrayStack.clear(); arrayStack.getObjectAtIndex(0); } </code></pre> Good luck!
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POJ-Unit Testing clear() method in an Array Stack
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. This table or related slice is empty.
UserOwnerUserId
1. USMeesh
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
2. VO
 singulars
 PostPostId
 PO
 UserUserId
 This table or related slice is empty.
 VoteTypeVoteTypeId
 VTUpMod
CommentsPostId
1. This table or related slice is empty.

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.