如何在 phpunit 测试中期待 diff() 方法？

Question

I'm a phpunit test beginner. I have a class like this:

class ClassA
{
    public function tracking($date)
    {
        //... something

        $now = new \DateTime();
        $days = $date->diff($now, false)->days;
        $hours = $date->diff($now, false)->h;
        $minutes = $date->diff($now, false)->i;

        //... something
        return true;
    }
}

Then, I want to unit test tracking() method. So I make a test like this:

class ClassATest extends TestCase
{
    /**
     * @dataProvider trackingDataProvider()
     * @param $params
     * @param $expected
     */
    public function testTracking($params, $expected)
    {
        $classA = new ClassA();
        $result = $classA->tracking($params['data']);
        $this->assertEquals($expected, $result);
    }

    public function trackingDataProvider()
    {
        return [
            'happy-case-1' => [
                'params' => [
                    'data' => new \DateTime()
                ],
                'expected' => true
            ],
        ];
    }
}

I run test and there is error: Error: Call to a member function diff() on array . How can I suppose diff() will return specified value to test? Please help!

Answer 1

You are trying to compare a DateTime object with $expected . I do not know what this variable really holds, since there is not type hinting. If it is a DateTime object, then you will need to get the correct format and type from it.

// Get as formatted string
(new \DateTime)->format('Y-m-d');

OR

// Get as timestamp integer
(new \DateTime)->getTimestamp();

The same must also be done with $result . So just as an explanatory example you should have below values at the end to check them for equality.

// as format
$expected = '2020-04-16';
$result = '2020-04-16';

// as timestamp
$expected = 1587033720;
$result = 1587033720;

Also if your function tracking returns a boolean, then you must do following.
Either assertTrue(); or assertEquals(true, $result)