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PO"Static methods are death to testability" - alternatives for alternative constructors?
 

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  1. PO"Static methods are death to testability" - alternatives for alternative constructors?
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    <p>It is being said that <a href="http://misko.hevery.com/2008/12/15/static-methods-are-death-to-testability/">"static methods are death to testability"</a>. If that is so, what is a viable alternative pattern for the below?</p> <pre><code>class User { private $phone, $status = 'default', $created, $modified; public function __construct($phone) { $this-&gt;phone = $phone; $this-&gt;created = new DateTime; $this-&gt;modified = new DateTime; } public static function getByPhone(PDO $pdo, $phone) { $stmt = $pdo-&gt;prepare('SELECT * FROM `users` WHERE `phone` = :phone'); $stmt-&gt;execute(compact('phone')); if (!$stmt-&gt;rowCount()) { return false; } $record = $stmt-&gt;fetch(PDO::FETCH_ASSOC); $user = new self($record['phone']); $user-&gt;status = $record['status']; $user-&gt;created = new DateTime($record['created']); $user-&gt;modified = new DateTime($record['modified']); return $user; } public function save(PDO $pdo) { $stmt = $pdo-&gt;prepare( 'INSERT INTO `users` (`phone`, `status`, `created`, `modified`) VALUES (:phone, :status, :created, :modified) ON DUPLICATE KEY UPDATE `status` = :status, `modified` = :modified'); $data = array( 'phone' =&gt; $this-&gt;phone, 'status' =&gt; $this-&gt;status, 'created' =&gt; $this-&gt;created-&gt;format('Y-m-d H:i:s'), 'modified' =&gt; date('Y-m-d H:i:s') ); return $stmt-&gt;execute($data); } ... } </code></pre> <p>This is just a cut down example. The class has a few more methods and properties and there's more validation when writing to the database etc. The guiding design principle behind this class is that it models a user as an object. Some of the object's properties cannot be modified after it has been created, like the phone number (which acts as a primary id), the date the user was created and so on. Other properties can only be altered according to strict business rules, which all have strictly validating setters and getters.</p> <p>The object does not represent a database record per se, the database is only seen as <em>one</em> possible form of permanent storage. As such, a database connector is not stored in the object but rather needs to be injected every time the object needs to interact with the database.</p> <p>When a new user is created, this looks like:</p> <pre><code>$user = new User('+123456789'); </code></pre> <p>When an existing user is restored from permanent storage, that looks like:</p> <pre><code>$pdo = new PDO('...'); $user = User::getByPhone($pdo, '+123456789'); </code></pre> <p>If I were to take the "death to testability" line seriously, this is supposedly bad. I am perfectly able to test this object though, since it is fully dependency injected and the <code>static</code> methods have no state. How could I do this any differently and avoid the use of <code>static</code> methods? Or rather, what exactly argues against <code>static</code> in this case? What makes this particular use of <code>static</code> methods so hard to test?</p>
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    1. COFor the above case, I'd go with a [Repository pattern](http://martinfowler.com/eaaCatalog/repository.html)
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    2. COIn this particular case static method is `death to extensibility`. You better tie your application parts via interfaces, not implementations
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    3. CO@Phil If I understand correctly, the Repository mostly seems to abstract the database queries, which I'd agree would be a useful thing to do. How would I initiate `private` properties without a static constructor through while still keeping all my privates encapsulated?
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