phpunit dataprovider out of scope - phpunit

Question

The class I'm testing:
class Calculate {
public $x;
public $y;
public function __construct($x, $y) {
$this->x = $x;
$this->y = $y;
}
public function add(): int {
return $this->x + $this->y;
}
}
My test code:
use PHPUnit\Framework\TestCase;
class CalculateTest extends TestCase {
public function additionProvider() {
return [
[1, 2],
[5, 8],
[-1, 10],
[66, 3],
[9, 4]
];
}
/**
* #dataProvider additionProvider
*/
public function testGetIsOk($x, $y): Calculate {
$c = new Calculate($x, $y);
var_dump($c);
$this->assertEquals($x, $c->x);
$this->assertEquals($y, $c->y);
return $c;
}
/**
* #depends testGetIsOk
*/
public function testAddIsNormal(Calculate $c):void {
$this->assertEquals($c->x + $c->y, $c->add());
}
}
There are 5 elements in the dataprovider, but the test result shows that the 6th test is error.
PHPUnit 6.3.0 by Sebastian Bergmann and contributors.
.....E 6 / 6 (100%)
Time: 97 ms, Memory: 8.00MB
There was 1 error:
1) CalculateTest::testAddIsNormal
TypeError: Argument 1 passed to CalculateTest::testAddIsNormal() must be an inst
ance of Calculate, null given
Thanks.

Answer 1

Ok, I check the issue on github, and I finally know that I cannot pass the result of a test that get data from data providers to another test.
There is it: https://github.com/sebastianbergmann/phpunit/issues/611