Please help. blue j test method

[chang-]

hi there. i am new to this forum and was wondering if anyone could help me

i have a test that i need to pass, but i am have no luck..

the test code is

 public void testCuttingGrassReducesGrassAndProducesHay() {
        
        Hay hay = field.cutGrass(100);
        assertNotNull(hay);
        assertEquals(100, hay.getUnits());
        assertEquals(0, field.getGrass());
    }

the method i need do write it for is :

public Hay cutGrass(int grassToCut)
    {

    
        if( grassToCut <= 0){
           throw new IllegalArgumentException("Cannot cut less than one unit of grass"); // if grass cut if less then one, exception thrown
        } 
        if( grassToCut > 100){
            throw new IllegalArgumentException("Cannot cut more grass than field contains"); // if grass cut contains more then in field exception is thrown.
        } 
  
        if (month >= 12){        // if month is more then or equal to 12 the grass cut goes is set back to 0.
           grass =0;
        }
        
        report("cut " + grassToCut + " units of grass");
        
        
        
        
        return hay;
    }

any help or if needed more info please ask..

thanks

[Junky]

The cutGrass method must create an instance of the Hay class and return it. Since we have no idea what the Hay class looks like we cannot offer more advice.

By the way the IDE (bluej) you use is irrelevant.

[chang-]

the hay class just has one constructor in it

public Hay(int units)
     {
 
        super(units, 1);
        
        
    }

sorry i dnt understand what you mean by blue j's is irrelvant?

[Junky]

You mentioned that you are using bluej as if it has some impact on your code. It doesn't. You would have the same problem if you wrote your code in Eclipse, Netbeans, JBuilder, ItelliJ, notpad etc. So mentioning what IDE you use is of no importance to us.

[Junky]

OK so now you have added code to the cutGrass method. What problem are you having? For starters I cannot see where you create an instance of the Hay class.

[chang-]

im having troube on writing the instance that calls from the hay class. so far i have

hay = new Hay();

i know its number of units should be in its parameter, but i dont know how to write it.

oh ok sorry i didnt knw

[chang-]

oh sorry i figured it out it was .

 hay = new Hay(grassToCut);

but when i run the test. the test says it expected 0 but got 100

[Norm]

   Hay hay = field.cutGrass(100);

In your first post you passed a parameter to a method. The code passes 100 to the method cutGrass().
A constructor is a special kind of method and you pass parameters to it the same way.

Look at the constructor and see what type of data is required. Then make sure the number of units is that data type.

[Junky]

Don't think about this in Java terms, think about it in real terms. After you cut the grass of a lawn/field/etc how much grass would there be?

[chang-]

more then 1 unit of grass?

[Norm]

What is the meaning of the parameter to the Hay constructor?
How do you know what value to give to it? Is there any documentation for the class that tells you?
No one here can know that number. It has to come from your professor or some part of the program.

[Junky]

Let me try another tack. If you lawn had 1000 units of grass and you cut 250 units and made it into hay, how much grass would your lawn still have?

[Junky]

I don't respond to private messages. If you have a question to ask then do it on the forum.

hi would it be possible if i could send you my code, to give u a beter understanding.

No. I believe people learn better if they write it themselves.

i would sitll have 750 units of grass left..
but i dont know how to write this as code

It is simple math.

int x = 1000;
int y = 250;
x = .......;

What would you replace the dots with so x had the final value of 750?