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PHPUnit: Verifying that array has a key with given value

Posted by: admin November 29, 2017 Leave a comment

Questions:

Given the following class:

<?php
class Example {
    private $Other;

    public function __construct ($Other)
    {
        $this->Other = $Other;
    }

    public function query ()
    {   
        $params = array(
            'key1' => 'Value 1'
            , 'key2' => 'Value 2'
        );

        $this->Other->post($params);
    }
}

And this testcase:

<?php
require_once 'Example.php';
require_once 'PHPUnit/Framework.php';

class ExampleTest extends PHPUnit_Framework_TestCase {

    public function test_query_key1_value ()
    {   
        $Mock = $this->getMock('Other', array('post'));

        $Mock->expects($this->once())
              ->method('post')
              ->with(YOUR_IDEA_HERE);

        $Example = new Example($Mock);
        $Example->query();
    }

How do I verify that $params (which is an array) and is passed to $Other->post() contains a key named ‘key1’ that has a value of ‘Value 1’?

I do not want to verify all of the array – this is just a sample code, in actual code the passed array has a lot more values, I want to verify just a single key/value pair in there.

There is $this->arrayHasKey('keyname') that I can use to verify that the key exists.

There is also $this->contains('Value 1'), which can be used to verify that the array has this value.

I could even combine those two with $this->logicalAnd. But this of course does not give the desired result.

So far I have been using returnCallback, capturing the whole $params and then doing asserts on that, but is there perhaps another way to do what I want?

Answers:

The $this->arrayHasKey('keyname'); method exists but its name is assertArrayHasKey :

// In your PHPUnit test method
$hi = array(
    'fr' => 'Bonjour',
    'en' => 'Hello'
);

$this->assertArrayHasKey('en', $hi);    // Succeeds
$this->assertArrayHasKey('de', $hi);    // Fails

Questions:
Answers:

In lieu of creating a re-usable constraint class, I was able to assert an array key’s value using the existing callback constraint in PHPUnit. In my use case, I needed to check for an array value in the second argument to a mocked method (MongoCollection::ensureIndex(), if anyone is curious). Here’s what I came up with:

$mockedObject->expects($this->once())
    ->method('mockedMethod')
    ->with($this->anything(), $this->callback(function($o) {
        return isset($o['timeout']) && $o['timeout'] === 10000;
    }));

The callback constraint expects a callable in its constructor, and simply invokes it during evaluation. The assertion passes or fails based on whether the callable returns true or false.

For a large project, I’d certainly recommend creating a re-usable constraint (as in the above solution) or petitioning for PR #312 to be merged into PHPUnit, but this did the trick for a one-time need. It’s easy to see how the callback constraint might be useful for more complicated assertions, too.

Questions:
Answers:

I ended up creating my own constraint class, based on the attribute one

<?php
class Test_Constraint_ArrayHas extends PHPUnit_Framework_Constraint
{
    protected $arrayKey;

    protected $constraint;

    protected $value;

    /**
     * @param PHPUnit_Framework_Constraint $constraint
     * @param string                       $arrayKey
     */
    public function __construct(PHPUnit_Framework_Constraint $constraint, $arrayKey)
    {
        $this->constraint  = $constraint;
        $this->arrayKey    = $arrayKey;
    }


    /**
     * Evaluates the constraint for parameter $other. Returns TRUE if the
     * constraint is met, FALSE otherwise.
     *
     * @param mixed $other Value or object to evaluate.
     * @return bool
     */
    public function evaluate($other)
    {
        if (!array_key_exists($this->arrayKey, $other)) {
            return false;
        }

        $this->value = $other[$this->arrayKey];

        return $this->constraint->evaluate($other[$this->arrayKey]);
    }

    /**
     * @param   mixed   $other The value passed to evaluate() which failed the
     *                         constraint check.
     * @param   string  $description A string with extra description of what was
     *                               going on while the evaluation failed.
     * @param   boolean $not Flag to indicate negation.
     * @throws  PHPUnit_Framework_ExpectationFailedException
     */
    public function fail($other, $description, $not = FALSE)
    {
        parent::fail($other[$this->arrayKey], $description, $not);
    }


    /**
     * Returns a string representation of the constraint.
     *
     * @return string
     */
    public function toString ()
    {
        return 'the value of key "' . $this->arrayKey . '"(' . $this->value . ') ' .  $this->constraint->toString();
    }


    /**
     * Counts the number of constraint elements.
     *
     * @return integer
     */
    public function count ()
    {
        return count($this->constraint) + 1;
    }


    protected function customFailureDescription ($other, $description, $not)
    {
        return sprintf('Failed asserting that %s.', $this->toString());
    }

It can be used like this:

 ... ->with(new Test_Constraint_ArrayHas($this->equalTo($value), $key));

Questions:
Answers:

In case you wish to do some complex testing on the parameter, and also have useful messages and comparisons, there is always the option of placing assertions within the callback.

e.g.

$clientMock->expects($this->once())->method('post')->with($this->callback(function($input) {
    $this->assertNotEmpty($input['txn_id']);
    unset($input['txn_id']);
    $this->assertEquals($input, array(
        //...
    ));
    return true;
}));

Notice that the callback returns true. Otherwise, it would always fail.

Questions:
Answers:

Sorry, I’m not an English speaker.

I think that you can test if a key exists in the array with the array_key_exists function, and you can test if the value exists with array_search

For example:

function checkKeyAndValueExists($key,$value,$arr){
    return array_key_exists($key, $arr) && array_search($value,$arr)!==false;
}

Use !== because array_search return the key of that value if exists and it may be 0.