public function testReadStream() { $mock = $this->getS3Client(); $mock->shouldReceive('registerStreamWrapper')->once()->andReturnUsing(function () { stream_wrapper_register('s3', 'StreamMock'); }); $adapter = new Adapter($mock, 'bucketname', 'prefix'); $result = $adapter->readStream('file.txt'); $this->assertInternalType('resource', $result['stream']); }