why is my mysqli instance failing when unit testing? - php

Question

I'm afraid I'm rather new to unit testing.
I have a PHP class called "dbRecord" that I use to abstract database tables/records and am trying to apply unit testing to it. When I do so though, the mysqli object that it uses seems to break.
As an example, I have a user class (an extension of the abstract dbRecord class) that works quite nicely if I create and save a user in a shell. That would be something like this:
$u = new userClass();
$u->setEmail('foo#bar.com');
$u->save();
That works very nicely if I use it in a web site or from a php shell. It creates an object, sets the e-mail value, and then saves it in the database, assigning the auto-incrementing id field back to the $u object.
If I try to create a unit test though, it fails upon saving the record. The error is happening when it tries to use mysqli::real_escape_string, but it happens with any other member of the mysqli object (I have tested that just in case). The error I get is:
mysqli::real_escape_string(): Couldn't fetch mysqli
So I assume there's something I'm failing to understand in the scope of things when doing the unit test. Here's the full code of the test I'm running:
<?php
require_once "../dbTemplate.php";
class TestOfUserClass extends PHPUnit_Framework_TestCase {
function testAssignUserValues(){
$usr = new userClass();
$usr->setEmail('foo#bar.com');
$this->assertTrue($usr->getEmail() == 'foo#bar.com');
$usr->save();
}
}
The code that's actually throwing that exception is in the save call. Here's what it looks like:
public function save(){
if($this->_isNewRecord){
// we're creating a new record
$query = "INSERT INTO `" . $this->_mysqli->real_escape_string($this->_tableName) . "`";
...
At this point I'm rather lost as to why it's not able to use that mysqli instance. Again, this works perfectly under regular usage (either through apache on a web page or through a php shell). It's only when using the test cases that it dies. I tried it with both Simpletest and PHPUnit, with the same results.
The structure of how that mysqli object is accessed goes like this:
In my test file (test1.php), "../dbTemplate.php" is included at the top.
In dbTemplate.php:
the mysqli object is created at the top, assigned to a variable called $mysqli.
the dbRecord abstract class is then defined
in that definition's construct, $this->_mysqli is assigned the value of $mysqli.
The test file is exactly as quoted above.
Then of course, I run "phpunit test1.php"
Does anyone see what I'm doing wrong here?

Answer 1

You will want to instantiate your object being tested in setUp() as opposed to the testing function. If you get an exception there then that usually means the path to dbTemplate.php can't be resolved from the test folder.
Without looking at the guts of your class it's hard to explain exactly, but generally speaking if you are not using autoloading, phpunit will not be able to resolve the locations of other files that are located outside of the testing root folder. Using an autoloader in bootstrap.php, however, helps with this. See PHPUnit Bootstrap and Autoloading Classes.