CODEWITHSUNDEEP
javamethodsprogram-entry-point
Jerryg225
Jerryg225

Reputation: 85

I have to test Java

I was told in my class that I have to write and test my code in the main method, I wrote it, but I dont know how to test it. How I am supposed to test my methods? I am supposed to take user input, and then get the get the first letter, last letter, etc.

import java.util.Scanner;

public class Word
{
    public static void main(String[] args)
    {

    }

    public String word;

    public void Word()
    {
        String word = "";
    }

    public void Word(String word1)
    {
        String word = word1;
    }

    public String getWord()
    {
        return word;
    }   

    public void setWord(String newWord)
    {
        String word = newWord;
    }

    public void getFirstLetter()
    {
        String firstLetter = word.substring(0, 1);
    }

    public void getLastLetter()
    {
        String lastLetter = word.substring(word.length() - 1, word.length());
    }

    public void removeFirstLetter()
    {
        String noFirstLetter = word.substring(1, word.length());
    }

    public void removeLastLetter()
    {
        String noLastLetter = word.substring(0, word.length() - 1);
    }
    public int findLetter (String parameter)
    {
        word.indexOf(parameter);
        return 1;
    }
}

Upvotes: 0

Views: 208

Answers (5)

matt
matt

Reputation: 2997

Agree with Jason. If you wanna test something, simply System.out.println() it. In your methods though, your return type is not a String but a void, so you could change that, and print it out on the main program run.

If not, just put the System.out.println() in your void methods. Shouldn't have much of a problem!

Upvotes: 0

stacker
stacker

Reputation: 69002

Just a hint: you're very close you need an instance of Word, than you can call your methods

public static void main(String[] args) {
      Word test = new Word();
      test.setWord("something");
      // here you might read javadoc of the String class on how to compare strings
}

EDIT: I overlooked this:

public void setWord(String newWord)
{
     String word = newWord;
}

The code you've written creates a variable word and newWord is assigned to it and then disappears. If you (obviously) want to set a member of a class you should use this wich references the instance (you created in main()).

public void setWord(String newWord) {
   this.word = newWord;
}

Upvotes: 1

Udo Held
Udo Held

Reputation: 12548

You should have a look at tools like junit.

You can create a simple Test class and test your class and its behavior.

imports ...;

public class MyTest{

    @Test
    public void testMyClass(){
        Word w= new Word();
        w.setWord("test");
        Assert.assertEquals(w.getFirstLetter(), "t");
    }
}

With tools like Eclipse you could nicely run such a test.

Upvotes: 1

Thomas
Thomas

Reputation: 88757

You test your methods by calling them with some defined input and compare the results with your expected output.

Example:

Suppose you have a method like this:

public static int add(int a, int b) {
  return a + b;
}

You'd test it like this:

int result = add( 3, 5);
if( result != 8 ) {
  //method is wrong
}

So basically you define a "contract" of what input the method gets and what the result should be (in terms of return value or other changed state). Then you check whether you get that result for your input and if so you can assume the method works correctly.

In order to be quite sure (you often can't be perfectly sure) you'd test the method several times with different types of input (as many as reasonable, to test different cases, e.g. short words, long words).

You often also test how your method handles wrong input, e.g. by passing null or empty strings.

Upvotes: 2

Jason Rae
Jason Rae

Reputation: 2663

Since I would say this is homework, I will try not to explicitly give the answer. In the main method, you should set your word, then call each method and print the output to verify it is correct.

Upvotes: 0

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