public function testAddEmpty() { $fileReader = new DummyFileReader(); $jsonFileReader = new Json($fileReader); $fileManager = new FileManager($jsonFileReader); $result = $fileManager->add(['key3' => 'value3']); $this->assertSame(40, $result); $result = $fileManager->getAll(); $this->assertSame([['key3' => 'value3']], $result); }