assertCount throws an Exception for a decorated Generator Iterator

[guilliamxavier]

Q	A
PHPUnit version	6.5.13 / 7.4.3
PHP version	7.0.31 / 7.1.22 / 7.2.10
Installation Method	(not relevant)

Given

(1) the following example class (in a vertically-compacted coding style):

/**
 * Wraps an Iterator: function calls are recorded, then forwarded to the wrapped iterator.
 */
class CallRecordingIterator implements \Iterator
{
    private $wrapped;
    private $recordedCalls = [];

    public function __construct(\Iterator $wrapped) { $this->wrapped = $wrapped; }

    private function recordCall($name) { $this->recordedCalls[] = $name; }

    public function rewind()  { $this->recordCall('rewind');         $this->wrapped->rewind(); }
    public function valid()   { $this->recordCall('valid');   return $this->wrapped->valid(); }
    public function key()     { $this->recordCall('key');     return $this->wrapped->key(); }
    public function current() { $this->recordCall('current'); return $this->wrapped->current(); }
    public function next()    { $this->recordCall('next');           $this->wrapped->next(); }

    public function getRecordedCalls() { return $this->recordedCalls; }
}

(2) a utility function:

function makeGenerator(array $array): \Generator
{
    foreach ($array as $key => $value) {
        yield $key => $value;
    }
}

(3) that the following test passes:

class MyTest extends \PHPUnit\Framework\TestCase
{
    public function testOk()
    {
        $generator = makeGenerator([1, 2]);
        $this->assertCount(2, $generator);
    }
}

then the (expected-to-pass) test:

    public function testIssue()
    {
        $generator = makeGenerator([1, 2]);
        $iterator = new CallRecordingIterator($generator);
        $this->assertCount(2, $iterator);
    }

results in 1 error:

Exception: Cannot rewind a generator that was already run

at phpunit/src/Framework/Constraint/Count.php:79 (same line for 6.5.13 and 7.4.3).

(A possible fix is to wrap the call to $iterator->rewind(); in a try-block [with the catch (\Exception $e) doing a return $count; or just swallow])

Note: the slightly-related pending PR #3316 keeps this behavior unchanged (the line is now here)

[stale]

This issue has been automatically marked as stale because it has not had activity within the last 60 days. It will be closed after 7 days if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed because it has not had activity since it was marked as stale. Thank you for your contributions.