diff --git a/test/expected/functions.out b/test/expected/functions.out
index 8f81c74..cf0d1ef 100644
--- a/test/expected/functions.out
+++ b/test/expected/functions.out
@@ -50,6 +50,18 @@ SELECT cosine_distance('[1,2]', '[0,0]');
              NaN
 (1 row)
 
+SELECT cosine_distance('[1,1]', '[1,1]');
+ cosine_distance 
+-----------------
+               0
+(1 row)
+
+SELECT cosine_distance('[1,1]', '[-1,-1]');
+ cosine_distance 
+-----------------
+               2
+(1 row)
+
 SELECT cosine_distance('[1,2]', '[3]');
 ERROR:  different vector dimensions 2 and 1
 SELECT avg(v) FROM unnest(ARRAY['[1,2,3]'::vector, '[3,5,7]']) v;
diff --git a/test/sql/functions.sql b/test/sql/functions.sql
index 3c6e949..39f3704 100644
--- a/test/sql/functions.sql
+++ b/test/sql/functions.sql
@@ -12,6 +12,8 @@ SELECT inner_product('[1,2]', '[3]');
 
 SELECT round(cosine_distance('[1,2]', '[2,4]')::numeric, 5);
 SELECT cosine_distance('[1,2]', '[0,0]');
+SELECT cosine_distance('[1,1]', '[1,1]');
+SELECT cosine_distance('[1,1]', '[-1,-1]');
 SELECT cosine_distance('[1,2]', '[3]');
 
 SELECT avg(v) FROM unnest(ARRAY['[1,2,3]'::vector, '[3,5,7]']) v;