diff --git a/spacy/tests/util.py b/spacy/tests/util.py
index c92129166..41673ab1d 100644
--- a/spacy/tests/util.py
+++ b/spacy/tests/util.py
@@ -46,20 +46,18 @@ def get_cosine(vec1, vec2):
 
 
 def assert_docs_equal(doc1, doc2):
-    # tokens
+    """Compare two Doc objects and assert that they're equal. Tests for tokens,
+    tags, dependencies and entities."""
     assert [ t.orth for t in doc1 ] == [ t.orth for t in doc2 ]
 
-    # tags
     assert [ t.pos for t in doc1 ] == [ t.pos for t in doc2 ]
     assert [ t.tag for t in doc1 ] == [ t.tag for t in doc2 ]
 
-    # parse
     assert [ t.head.i for t in doc1 ] == [ t.head.i for t in doc2 ]
     assert [ t.dep for t in doc1 ] == [ t.dep for t in doc2 ]
     if doc1.is_parsed and doc2.is_parsed:
         assert [ s for s in doc1.sents ] == [ s for s in doc2.sents ]
 
-    # entities
     assert [ t.ent_type for t in doc1 ] == [ t.ent_type for t in doc2 ]
     assert [ t.ent_iob for t in doc1 ] == [ t.ent_iob for t in doc2 ]
     assert [ ent for ent in doc1.ents ] == [ ent for ent in doc2.ents ]