B2B-2255: "Currency" GraphQl query has no cache identity

Author: joanhe

app/code/Magento/DirectoryGraphQl/Plugin/Currency.php

@@ -13,7 +13,7 @@
 use Magento\Directory\Model\Currency as CurrencyModel;
 
 /**
- * Currency plugin
+ * Currency plugin triggers clean page cache and provides currency cache identities
  */
 class Currency implements IdentityInterface
 {
@@ -33,7 +33,7 @@ public function __construct(ManagerInterface $eventManager)
     }
 
     /**
-     * Add graphql store config tag to the store group cache identities.
+     * Trigger clean cache by tags after save rates
      *
      * @param CurrencyModel $subject
      * @param CurrencyModel $result

app/code/Magento/DirectoryGraphQl/etc/di.xml

@@ -9,7 +9,9 @@
     <type name="Magento\Framework\App\Cache\Tag\Strategy\Factory">
         <arguments>
             <argument name="customStrategies" xsi:type="array">
-                <item name="Magento\Framework\App\Config\ValueInterface" xsi:type="object">\Magento\DirectoryGraphQl\Model\Cache\Tag\Strategy\CurrencyConfig</item>
+                <item name="Magento\Framework\App\Config\ValueInterface" xsi:type="object">
+                    Magento\DirectoryGraphQl\Model\Cache\Tag\Strategy\CurrencyConfig
+                </item>
             </argument>
         </arguments>
     </type>

dev/tests/api-functional/testsuite/Magento/GraphQl/Directory/CurrencyCacheTest.php

@@ -501,13 +501,13 @@ public function testCachePurgedWithExchangeRateChange(): void
 
         // Query second store currency
         $secondStoreCode = 'second_store_view';
-        $responseThirdStore = $this->graphQlQueryWithResponseHeaders(
+        $responseSecondStore = $this->graphQlQueryWithResponseHeaders(
             $query,
             [],
             '',
             ['Store' => $secondStoreCode]
         );
-        $secondStoreCacheId = $responseThirdStore['headers'][CacheIdCalculator::CACHE_ID_HEADER];
+        $secondStoreCacheId = $responseSecondStore['headers'][CacheIdCalculator::CACHE_ID_HEADER];
         // Verify we obtain a cache MISS at the 1st time
         $secondStoreResponse = $this->assertCacheMissAndReturnResponse(
             $query,