Fix for Magento Issue 13950 Solution: Use currency code instead currency symbol in cache key generating to get unique cache of these block for different currencies.

Author: nuzil

app/code/Magento/CatalogWidget/Block/Product/ProductsList.php

@@ -160,7 +160,7 @@ public function getCacheKeyInfo()
 
         return [
             'CATALOG_PRODUCTS_LIST_WIDGET',
-            $this->getPriceCurrency()->getCurrencySymbol(),
+            $this->getPriceCurrency()->getCurrency()->getCode(),
             $this->_storeManager->getStore()->getId(),
             $this->_design->getDesignTheme()->getId(),
             $this->httpContext->getValue(\Magento\Customer\Model\Context::CONTEXT_GROUP),

app/code/Magento/CatalogWidget/Test/Unit/Block/Product/ProductsListTest.php

@@ -147,7 +147,9 @@ public function testGetCacheKeyInfo()
         $this->request->expects($this->once())->method('getParam')->with('page_number')->willReturn(1);
 
         $this->request->expects($this->once())->method('getParams')->willReturn('request_params');
-        $this->priceCurrency->expects($this->once())->method('getCurrencySymbol')->willReturn('$');
+        $currency = $this->createMock(\Magento\Directory\Model\Currency::class);
+        $currency->expects($this->once())->method('getCode')->willReturn('USD');
+        $this->priceCurrency->expects($this->once())->method('getCurrency')->willReturn($currency);
 
         $this->serializer->expects($this->any())
             ->method('serialize')
@@ -157,7 +159,7 @@ public function testGetCacheKeyInfo()
 
         $cacheKey = [
             'CATALOG_PRODUCTS_LIST_WIDGET',
-            '$',
+            'USD',
             1,
             'blank',
             'context_group',