diff --git a/spacy/tests/util.py b/spacy/tests/util.py
index 56aeb5223..2f474a926 100644
--- a/spacy/tests/util.py
+++ b/spacy/tests/util.py
@@ -79,9 +79,9 @@ def add_vecs_to_vocab(vocab, vectors):
     """Add list of vector tuples to given vocab. All vectors need to have the
     same length. Format: [("text", [1, 2, 3])]"""
     length = len(vectors[0][1])
-    vocab.resize_vectors(length)
+    vocab.clear_vectors(length)
     for word, vec in vectors:
-        vocab[word].vector = vec
+        vocab.set_vector(word, vec)
     return vocab