MAGETWO-64625: Implement API for file downloading by MA

add base64 encoding for transferring binary vector

Author: valdislav

app/code/Magento/Analytics/Model/LinkProvider.php

@@ -61,7 +61,7 @@ public function get()
                 UrlInterface::URL_TYPE_MEDIA
             ) . $fileInfo->getPath()
         );
-        $link->setInitializationVector($fileInfo->getInitializationVector());
+        $link->setInitializationVector(base64_encode($fileInfo->getInitializationVector()));
         return $link;
     }
 }

app/code/Magento/Analytics/Test/Unit/Model/LinkProviderTest.php

@@ -123,7 +123,7 @@ public function testGet()
         );
         $this->linkInterfaceMock->expects($this->once())
             ->method('setInitializationVector')
-            ->with($fileInitializationVector);
+            ->with(base64_encode($fileInitializationVector));
         $this->assertEquals($this->linkInterfaceMock, $this->linkProvider->get());
     }
 

dev/tests/api-functional/testsuite/Magento/Analytics/Api/LinkProviderTest.php

@@ -58,7 +58,7 @@ public function testGetAll()
         ];
         $response = $this->_webApiCall($serviceInfo);
         $this->assertEquals(2, count($response));
-        $this->assertEquals($fileInfo->getInitializationVector(), $response['initialization_vector']);
+        $this->assertEquals($fileInfo->getInitializationVector(), base64_encode($response['initialization_vector']));
         $this->assertEquals(
             $storeManager->getStore()->getBaseUrl(
                 UrlInterface::URL_TYPE_MEDIA