It passes the final challenge for the course, but...

Question

Here's the code that passed (after hours and hours of trial and error):   
```java
@Test
public void vendingOperationSuccessful() throws Exception {
    assertEquals(0, machine.getRunningSalesTotal());  
}
```
Don't have a clue as to WHY that was the correct answer, though. :confused:
In my way of thinking it seems to me that 
a one line assert (added to the existing 'vendingWhenStockedReturnsItem()' test) 
would have been more "right" somehow:
```java
@Test
public void vendingWhenStockedReturnsItem() throws Exception {
    machine.addMoney(75);

Item item = machine.vend("A1");

assertEquals("Twinkies", item.getName());

assertEquals(75, machine.getRunningSalesTotal());
}
```
But I guess I was just being stupid in using the following train of thought (tracing though what was initially given for the challenge):
```java
runningSalesTotal = 0;         
```
(see the the 'public VendingMachine' code inside 'VendingMachine.java')
```java
runningSalesTotal += price;    
```
(see the the 'public Item vend' code inside 'VendingMachine.java')
Once the 'runningSalesTotal' can be retrieved using this getter code (also from inside 'VendingMachine.java'):
```java
public int getRunningSalesTotal() {
    return runningSalesTotal;
}
```
Then use 'machine' in place of vending machine 
(looking at the '@Before' lines of code):
```java
 machine = new VendingMachine(notifier, 10, 10, 10);
```
Then the 'asserts' (if true test) should be that machine.getRunningSalesTotal() == 75.
after the tested restock (sale) using this line of code  in the @Before code section
(where the final argument represents the price paid):
```java
machine.restock("A1", "Twinkies", 10, 30, 75);
```
At least that's the way it seems to me..but maybe I guess I just misunderstood everything...
Anyway...I got my points/badges for this course so I guess it doesn't matter 
if I actually learned anything -- on to the next course for more points and badges
Hopefully, though, this forum thread/post saves some people a lot of random guessing..

Evan Demaris · Accepted Answer

Hi james,
You actually did a really great job on this - and it sounds like you understand exactly what's going on with the code. Your posted answer:
```Java
@Test
public void vendingOperationSuccessful() throws Exception {
    assertEquals(0, machine.getRunningSalesTotal());  
}
```
Passes, because it's asserting that the running sales total will be some number. However, you're completely correct that the assert added to the vendingWhenStockedReturnsItem() is more "right". While your first answer is passing because it technically meets the requirements that the Challenge is checking against, the second answer is actually doing what the Challenge 'meant' for you to do. So really, a great answer would just be to add a new function that is identical to the vendingWhenStockedReturnsItem() function, but just adding your assert and changing the name. Adding the below code would pass the Challenge, and would be actually checking what it should:
```Java
   @Test
    public void vendingOperationSuccessful() throws Exception {
        machine.addMoney(75);
    Item item = machine.vend("A1");

assertEquals("Twinkies", item.getName());

assertEquals(75, machine.getRunningSalesTotal());
}
```
It might not feel like you're really advancing, because you keep pushing forward into areas that you aren't familiar with - you're challenging yourself, you are supposed to be having trouble working things out! But you really are learning as you go along. If you ever get completely stuck somewhere, remember that you aren't alone, we all get stuck sooner or later. Sometimes the best solution is to work your way through, sometimes it makes more sense to ask for help or see if someone else has already come up with a good way to do it. You shouldn't be afraid to ask for help here, too, because there are a lot of people who are happy to answer questions and help you learn.
The only bad coder is the one who gives up before they get good at it!

Allan Collado · Answer

@Test
    public void vendingOperationSuccessful() throws Exception {
        assertEquals(0, machine.getRunningSalesTotal());  
    }
 Hi,  I understand  your code  but what I don't understand
is why you are expecting  0!? for my understanding Im expecting a number bigger than the one in getRunningSalesTotal()?

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james white

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It passes the final challenge for the course, but...

2 Answers

Evan Demaris

Evan Demaris

Hannah Flynn

Hannah Flynn

Evan Demaris

Evan Demaris

Allan Collado

Allan Collado