Unit Testing Class
Unit testing is an approach to software development in which tests are written for each function in your application. If you are not familiar with the concept you might do a little googling on the subject.
CodeIgniter's Unit Test class is quite simple, consisting of an evaluation function and two result functions. It's not intended to be a full-blown test suite but rather a simple mechanism to evaluate your code to determine if it is producing the correct data type and result.
Initializing the Class
Like most other classes in CodeIgniter, the Unit Test class is initialized in your controller using the $this->load->library function:
$this->load->library('unit_test');
Once loaded, the Unit Test object will be available using: $this->unit
Running Tests
Running a test involves supplying a test and an expected result to the following function:
$this->unit->run( test, expected result, 'test name' );
Where test is the result of the code you wish to test, expected result is the data type you expect, and test name is an optional name you can give your test. Example:
$test = 1 + 1;
$expected_result = 2;
$test_name = 'Adds one plus one';
$this->unit->run($test, $expected_result, $test_name);
The expected result you supply can either be a literal match, or a data type match. Here's an example of a literal:
$this->unit->run('Foo', 'Foo');
Here is an example of a data type match:
$this->unit->run('Foo', 'is_string');
Notice the use of "is_string" in the second parameter? This tells the function to evaluate whether your test is producing a string as the result. Here is a list of allowed comparison types:
- is_string
- is_bool
- is_true
- is_false
- is_int
- is_numeric
- is_float
- is_double
- is_array
- is_null
Generating Reports
You can either display results after each test, or your can run several tests and generate a report at the end. To show a report directly simply echo or return the run function:
echo $this->unit->run($test, $expected_result);
To run a full report of all tests, use this:
echo $this->unit->report();
The report will be formatted in an HTML table for viewing. If you prefer the raw data you can retrieve an array using:
echo $this->unit->result();
Strict Mode
By default the unit test class evaluates literal matches loosely. Consider this example:
$this->unit->run(1, TRUE);
The test is evaluating an integer, but the expected result is a boolean. PHP, however, due to it's loose data-typing will evaluate the above code as TRUE using a normal equality test:
if (1 == TRUE) echo 'This evaluates as true';
If you prefer, you can put the unit test class in to strict mode, which will compare the data type as well as the value:
if (1 === TRUE) echo 'This evaluates as FALSE';
To enable strict mode use this:
$this->unit->use_strict(TRUE);
Enabling/Disabling Unit Testing
If you would like to leave some testing in place in your scripts, but not have it run unless you need it, you can disable unit testing using:
$this->unit->active(FALSE)
Creating a Template
If you would like your test results formatted differently then the default you can set your own template. Here is an example of a simple template. Note the required pseudo-variables:
$str = '
<table border="0" cellpadding="4" cellspacing="1">
{rows}
<tr>
<td>{item}</td>
<td>{result}</td>
</tr>
{/rows}
</table>';
$this->unit->set_template($str);
Note: Your template must be declared before running the unit test process.