Test Driven Development example - Part 4 (Simple Unit Testing for Java with NetBeans)

Lets code the all tests in the to do list. (this should be done one by, for the tutorial i used it just to show how to do it)
The FibonacciTest.java file will be look like

 
 
package tdd;

import org.junit.Test;
import static org.junit.Assert.*;
 
public class FibonacciTest {

    @Test
    public void testGetFibonacci_0() {
        int x = 0;
        Fibonacci instance = new Fibonacci();
        int expResult = 0;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_1() {
        int x = 1;
        Fibonacci instance = new Fibonacci();
        int expResult = 1;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_2() {
        int x = 2;
        Fibonacci instance = new Fibonacci();
        int expResult = 1;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_3() {
        int x = 3;
        Fibonacci instance = new Fibonacci();
        int expResult = 2;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_4() {
        int x = 4;
        Fibonacci instance = new Fibonacci();
        int expResult = 3;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_5() {
        int x = 5;
        Fibonacci instance = new Fibonacci();
        int expResult = 5;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

    @Test
    public void testGetFibonacci_6() {
        int x = 6;
        Fibonacci instance = new Fibonacci();
        int expResult = 8;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }
}

Just run the tests and see before progress. :)
we added 4 tests, they will fail.

lets pass the 4th test.
Edit the Fibonacci.java like below to produce the first 4 Fibonacci number correctly

 
package tdd;

public class Fibonacci {

    public int getFibonacci(int x) {
        int result = 0;
        if (x == 1 || x == 2) {
            result = 1;
        } else if (x==3) {
            result = 2;
        }
        return result;
    }
}

The result will be

Lets write in the typical way to pass all the test correctly.

 
package tdd;

public class Fibonacci {

    public int getFibonacci(int x) {
        int result = 0;
        if (x == 1 || x == 2) {
            result = 1;
        } else if (x == 3) {
            result = 2;
        } else if (x == 4) {
            result = 3;
        } else if (x == 5) {
            result = 5;
        } else if (x == 6) {
            result = 8;
        }
        return result;
    }
}

Then all the tests will be passed. We can do this type of code for every other input as well. But we know that it cannot be done manually :) so we have to seek for a pattern in this input outputs.
And there is a pattern. The nth Fibonacci number is equal to the
(n-1)th Fibonacci number + (n-2)th Fibonacci number
Lets modify the code to produce every Fibonacci number correctly

 
package tdd;

public class Fibonacci {

    public int getFibonacci(int x) {
        int fibNumber = 1;
        if (x == 0) {
            fibNumber = 0;
        } else if (x <= 2) {
            fibNumber = 1;
        } else {
            fibNumber = getFibonacci(x - 1) + getFibonacci(x - 2);
        }
        return fibNumber;
    }
}

Lets check the correctness of the program by some random test cases. :)
Lets add this test to check some other known Fibonacci numbers.

 
 @Test
    public void testFibonacci() {
        Fibonacci fibonacci = new Fibonacci();

        int cases[][] = {{7, 13}, {8, 21}, {9, 34}, {10, 55}, {11, 89}, {18, 2584}, {19, 4181}};
        for (int i = 0; i < cases.length; i++) {
            assertEquals(cases[i][1], fibonacci.getFibonacci(cases[i][0]));
        }

    }

Looks like our code pass those random cases as well. ok now we can assume that our code is working :)

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Test Driven Development example - Part 3 (Simple Unit Testing for Java with NetBeans)

Our 2nd task in the to do list is,
[2] getFibonacci(1) ==> 1
now we have a passing code.
we have to make it fail. to that we can ask it the 1st Fibonacci number.
change the FibonacciTest.java file as below.
Here i have introduced a new method for check the result for input 1. Then it will be easy to identify what is going on.

 
 
package tdd;

import org.junit.Test;
import static org.junit.Assert.*;

public class FibonacciTest {

    @Test
    public void testGetFibonacci_0() {
        int x = 0;
        Fibonacci instance = new Fibonacci();
        int expResult = 0;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }
    @Test
    public void testGetFibonacci_1() {
        int x = 1;
        Fibonacci instance = new Fibonacci();
        int expResult = 1;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }
}

Then run the code and see the result. You will see that our first test will pass and the second one is failing. That is because the getFibonacci method only return value '0' for any input.
So our test is failing. And now we have a failing code. :)

Lets make it pass. To do that we have to edit the getFibonacci method to correctly return the first 2 Fibonacci numbers.
Do the following changes in Fibonacci.java file

 
 
package tdd;

public class Fibonacci {

    public int getFibonacci(int x) {
        int result = 0;
        if (x == 1) {
            result = 1;
        }
        return result;
    }
}

Run the test file and see the results.

seems it is working :)
our second task is done. lets look at our to do list :)

[1] getFibonacci(0) ==> 0
[2] getFibonacci(1) ==> 1
[3] getFibonacci(2) ==> 1
[4] getFibonacci(3) ==> 2
[5] getFibonacci(4) ==> 3
[6] getFibonacci(5) ==> 5
[7] getFibonacci(6) ==> 8


lets move to our next task
[3] getFibonacci(2) ==> 1
and again we have a passing code. we have to make it fail. when we pass the '2' as input it will fail. make another testing method to do it.

 
 
 @Test
    public void testGetFibonacci_2() {
        int x = 2;
        Fibonacci instance = new Fibonacci();
        int expResult = 1;
        int result = instance.getFibonacci(x);
        assertEquals(expResult, result);
    }

result will be looks like

ok our 3rd test is failing. :) lets make it pass. we have to correctly produce first 3 Fibonacci numbers to that.
Edit the Fibonacci.java like below

 
 
package tdd;

public class Fibonacci {

    public int getFibonacci(int x) {
        int result = 0;
        if (x == 1 || x == 2) {
            result = 1;
        }
        return result;
    }
}

and the result will be

So we have completed our 3rd task also. :)
we can use if else and do that for any input. A brute force method. But after some time we may able to identify a pattern of the inputs and the out puts.

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Test Driven Development example - Part 2 (Simple Unit Testing for Java with NetBeans)

After following the  previous work now we are good to code :)

First of all lets edit the Fibonacci.java file. lets add a new method.

package tdd;
 
public class Fibonacci {

    public void getFibonacci(int x) {
    }
}

Now edit the FibonacciTest.java file like below.

 
package tdd;

import org.junit.Test;
import static org.junit.Assert.*;

public class FibonacciTest {

    public FibonacciTest() {
    }

    @Test
    public void testGetFibonacci() {
        fail("The test case is a prototype.");
    }
}

now just right click on the FibonacciTest.java file and run it.
The result will be as below.

Ok now we have a failing code :) We have to make it pass now.
lets make a to do list.

[1] getFibonacci(0) ==> 0
[2] getFibonacci(1) ==> 1
[3] getFibonacci(2) ==> 1
[4] getFibonacci(3) ==> 2
[5] getFibonacci(4) ==> 3
[6] getFibonacci(5) ==> 5
[7] getFibonacci(6) ==> 8

case 1) we have to generate the first Fibonacci number. now we have a failing code. lets make it pass and return the correct answer (0) for input (0)
change the Fibonacci.java files getFibonacci method as follows. So that it return the correct answer to the input '0'. If you remember the 3rd point it says that "we are not allowed to write any more production code than is sufficient to pass the one failing unit test" . so we have a failing test case. We have to write the code only to pass that failing code.

 
 
package tdd;
 
public class Fibonacci {

    public int getFibonacci(int x) {
        return 0;
    }
}

Then change the FibonacciTest.java file as below.

 
 
package tdd;

import org.junit.Test;
import static org.junit.Assert.*;

public class FibonacciTest {

    public FibonacciTest() {
    }

    @Test
    public void testGetFibonacci() {
        //fail("The test case is a prototype.");
        
        // this is the xth fibonacci number
        int x = 0;
        //make an instance of the Fibonacci class to access
        //getFibonacci method
        Fibonacci instance = new Fibonacci();
        // this is our expected result
        int expResult = 0;
        // get the actual  result
        int result = instance.getFibonacci(x);
        // this will  check and compare the result and the 
        // expected result. If both match test will pass.
        assertEquals(expResult, result);

    }
}

The comments will help you to understand what is going on. :)
lets run the code and see

wow we have just made our failing test case passed. :)
Our code will correctly return the 0th Fibonacci number (lets use the 0th indexing)
our first task in the to do list is done :)
[1] getFibonacci(0) ==> 0
[2] getFibonacci(1) ==> 1
[3] getFibonacci(2) ==> 1
[4] getFibonacci(3) ==> 2
[5] getFibonacci(4) ==> 3
[6] getFibonacci(5) ==> 5
[7] getFibonacci(6) ==> 8

way to go :)

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Test Driven Development example (Getting started)

There was a workshop in our university to give us an introduction about TDD by OrangeHRM. The followings are based on those experience. 

You can read about TDD here .
Simply the TDD coding process has 3 rules.(for more details refer this)

 1) You are not allowed to write any production code unless it is to make a failing unit test pass.  
 2) You are not allowed to write any more of a unit test than is sufficient to fail; and compilation failures are failures. 
 3) You are not allowed to write any more production code than is sufficient to pass the one failing unit test.
 Here i used java and the net beans IDE to do the example.

We have to develop a program which give us the n-th Fibonacci number.

Let's create a new project called TDD first. Then create a new JUnit test. (right click the project and select JUnit test- If it is not there use other option to find it)

First create a class in Source Packages.(name it  Fibonacci )Then create a test class in the Test Packages.(name it FibonacciTest)(Don't worry if you haven't the Test Packages yet, just right click the project and create a new test, it will create a new Test Packages section ). (you can do it in 3 ways)

In the Test Packages ,
1) Create a normal java class and we can import the relevant Unit Test packages later.
2) Create a JUnit test and give the name "FibonacciTest" manually.(This will automatically call the relevant imports)
3) Create a JUnit test class by using Test for Existing class. (It will automatically set the name "FibonacciTest" and will  call  the imports as well)

Then add the JUnit library (here i used JUnit 4.10) to the Test Libraries.

The Project folder structure will  looks like this.

 

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Create a Chrome extenstion to highlight paragraphs on user click event

I started to create a Google chrome extension to highlight the web content. As the first step i was able to create this extension which highlight the whole "p" tag when a user click on it. There are 4 file. (manifest.json, tabcolor.js ,color.js,popup.html (to call the js files,but not necessary,there are other ways )) the manifest.json file looks like

   
{
  "name": " page color 2.",
  "version": "1.0",
  "permissions": [
    "tabs", "http://*/*", "https://*/*"
  ],
  "browser_action": {
      "default_title": "Set this page's color.",
      "default_icon": "icon.png",
      "default_popup": "popup.html"
  },
  "manifest_version": 2
}

the popup.html file will looks like

<!doctype html>
<html>
  <head>
    <title>Set Page Color Popup</title>
     <script src="color2.js"></script>
  </head>  
</html>

the color.js file looks like

   

function clickcolor(e) {
   chrome.tabs.executeScript(null,{file : "tabcolor.js"});
   window.close();
}

document.addEventListener('DOMContentLoaded', function () {
     clickcolor();
 
}); 

the tabcolor.js file looks like

  
var divs = document.getElementsByTagName("p");
  
    for(var d in divs) {
    divs[d].addEventListener('click',function(){this.style.background='yellow';}); 
     }
 

It will appears to be like this ,

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