React\Promise\PromiseTest\CancelTestTrait::cancelShouldCallCancellerOnlyOnceIfCancellerResolves PHP Method

    public function cancelShouldCallCancellerOnlyOnceIfCancellerResolves()
    {
        $mock = $this->createCallableMock();
        $mock->expects($this->once())->method('__invoke')->will($this->returnCallback(function ($resolve) {
            $resolve();
        }));
        $adapter = $this->getPromiseTestAdapter($mock);
        $adapter->promise()->cancel();
        $adapter->promise()->cancel();
    }