diff --git a/tests/test-random b/tests/test-random
index 1b3dc3f..e42e2e5 100755
--- a/tests/test-random
+++ b/tests/test-random
@@ -47,7 +47,9 @@ def generate_statement(conn, table, column_values, all_values):
         if random.randint(0, 1) == 0:
             values = all_values
         value = values[random.randint(0, len(values) - 1)]
-        query += field + ' ' + op + ' ' + str(value)
+        if random.randint(0, 5) == 0:
+            query += ' NOT '
+        query += '(' + field + ' ' + op + ' ' + str(value) + ')'
 
     if random.randint(0, 3) == 0:
         how_many = random.randint(0, 15)