Extending the xdebug_start_code_coverage() and xdebug_get_code_coverage() functions - PHP

To be frank, the “xdebug_start_code_coverage()” and “xdebug_get_code_coverage()” functions really start to shine when used to keep track of which lines are executed by a PHP application based on a certain condition.

To exemplify this specific situation, I’m going to use the already familiar “User” class that you learned in the prior section, along with a simple script which will change its execution flow according to a semi-random value generated by the built-in PHP “rand()” function.

Of course, in this case, the “xdebug_start_code_coverage()” and “xdebug_get_code_coverage()” functions will be employed to keep track of which code block is executed by the script in question.

The code sample that shows how to use these functions with a basic conditional statement is as follows:

class User{

private $firstName;

private $lastName;

private $email;

public function __construct($firstName,$lastName,$email){

if(!$firstName){

throw new Exception('Invalid parameter First Name.');

}

if(!$lastName){

throw new Exception('Invalid parameter Last Name.');

}

if(!$email){

throw new Exception('Invalid parameter Email.');

}

$this->firstName=$firstName;

$this->lastName=$lastName;

$this->email=$email;

}

// get first name

public function getFirstName(){

return $this->firstName;

}

// get last name

public function getLastName(){

return $this->lastName;

}

// get email

public function getEmail(){

return $this->email;

}

}

xdebug_start_code_coverage();

$user=new User('John','Doe','john@domain.com');

if(rand(1,10)<5){

echo 'First Name :'.$user->getFirstName().'<br />';

echo 'Last Name :'.$user->getLastName().'<br />';

}

else{

echo 'Email :'.$user->getEmail().'<br />';

}

var_dump(xdebug_get_code_coverage());

/* displays the following when 'rand()' function returns a value < 5

First Name :John

Last Name :Doe

array

'/path/to/example/program_flow_debug.php' =>

array

8 => int 1

11 => int 1

14 => int 1

17 => int 1

18 => int 1

19 => int 1

20 => int 1

23 => int 1

36 => int 1

37 => int 1

38 => int 1

39 => int 1

40 => int 1

44 => int 1

*/

Definitely, the above example shows in a nutshell how useful the “xdebug_start_code_coverage()” and “xdebug_get_code_coverage()” functions can be when it comes to debugging conditional statements within a PHP script.

In this case, the “rand()” PHP native function is utilized in conjunction with an “if” conditional statement to create a simple situation where there are two blocks of code that can be invoked. Logically, this example shows the sequence of lines executed when the “rand()” function returns a value less than 5, in this way demonstrating the functionality of the “xdebug_start_code_coverage()” and “xdebug_get_code_coverage()” functions.

So far, so good, right? You hopefully understand how simple it is to debug conditional statements with the two functions shown before. The previous script would be rather incomplete, however, if I don’t show you the output it produces when the value returned by the “rand()” function is greater than 5.

Therefore, in the last section of this article I will represent this condition through a functional script, in this manner finishing this quick overview on using the “xdebug_start_code_coverage()” and “xdebug_get_code_coverage()” functions included with the X-debug extension.

Click on the link below and read the next few lines, please.