Add source to imported subscribers

[MAILPOET-1377]

lib/Subscribers/ImportExport/Import/Import.php

@@ -9,6 +9,7 @@ use MailPoet\Models\Subscriber;
 use MailPoet\Models\SubscriberCustomField;
 use MailPoet\Models\SubscriberSegment;
 use MailPoet\Subscribers\ImportExport\ImportExportFactory;
+use MailPoet\Subscribers\Source;
 use MailPoet\Util\Helpers;
 
 class Import {
@@ -108,6 +109,7 @@ class Import {
         // add, if required, missing required fields to new subscribers
         $new_subscribers = $this->addMissingRequiredFields($new_subscribers);
         $new_subscribers = $this->setSubscriptionStatusToSubscribed($new_subscribers);
+        $new_subscribers = $this->setSource($new_subscribers);
         $created_subscribers =
           $this->createOrUpdateSubscribers(
             'create',
@@ -286,6 +288,17 @@ class Import {
     return $subscribers_data;
   }
 
+  function setSource($subscribers_data) {
+    $subscribers_count = count($subscribers_data['data'][key($subscribers_data['data'])]);
+    $subscribers_data['fields'][] = 'source';
+    $subscribers_data['data']['source'] = array_fill(
+      0,
+      $subscribers_count,
+      Source::IMPORTED
+    );
+    return $subscribers_data;
+  }
+
   function getSubscribersFields($subscribers_fields) {
     return array_values(
       array_filter(

tests/unit/Subscribers/ImportExport/Import/ImportTest.php

@@ -452,6 +452,8 @@ class ImportTest extends \MailPoetTest {
     expect($new_subscribers)->count(2);
     expect($new_subscribers[0]->status)->equals('subscribed');
     expect($new_subscribers[1]->status)->equals('subscribed');
+    expect($new_subscribers[0]->source)->equals('imported');
+    expect($new_subscribers[1]->source)->equals('imported');
   }
 
   function testItRunsImport() {