diff --git a/test/VocabularyGeneratorTest.cpp b/test/VocabularyGeneratorTest.cpp
index dc0a130995..9bf7cfd2a3 100644
--- a/test/VocabularyGeneratorTest.cpp
+++ b/test/VocabularyGeneratorTest.cpp
@@ -193,7 +193,7 @@ TEST_F(MergeVocabularyTest, bla) {
   VocabularyMerger::VocMergeRes res;
   {
     VocabularyMerger m;
-    m.mergeVocabulary(_basePath, 2, StringSortComparator());
+    res = m.mergeVocabulary(_basePath, 2, StringSortComparator());
   }
 
   // No language tags in text file