diff --git a/src/Feeds/Fetcher/HttpFetcher.php b/src/Feeds/Fetcher/HttpFetcher.php
index bc15a15b..62c3ca63 100644
--- a/src/Feeds/Fetcher/HttpFetcher.php
+++ b/src/Feeds/Fetcher/HttpFetcher.php
@@ -100,6 +100,7 @@ class HttpFetcher extends PluginBase implements ClearableInterface, FetcherInter
     $sink = $this->fileSystem->realpath($sink);
 
     try {
+      // Get cache key if caching is enabled.
       $cache_key = $this->useCache() ? $this->getCacheKey($feed) : FALSE;
       $response = $this->get($feed->getSource(), $sink, $cache_key);
     }
diff --git a/tests/src/Unit/Feeds/Fetcher/HttpFetcherTest.php b/tests/src/Unit/Feeds/Fetcher/HttpFetcherTest.php
index 3358b9ef..d5b23615 100644
--- a/tests/src/Unit/Feeds/Fetcher/HttpFetcherTest.php
+++ b/tests/src/Unit/Feeds/Fetcher/HttpFetcherTest.php
@@ -68,6 +68,9 @@ class HttpFetcherTest extends FeedsUnitTestCase {
     $file_system->realpath(Argument::type('string'))->will(function ($args) {
       return realpath($args[0]);
     });
+    $file_system->unlink(Argument::type('string'))->will(function ($args) {
+      return TRUE;
+    });
 
     $this->fetcher = new HttpFetcher(['feed_type' => $feed_type], 'http', [], $client, $cache, $file_system->reveal());
     $this->fetcher->setStringTranslation($this->getStringTranslationStub());