diff --git a/lib/simplecov/result_merger.rb b/lib/simplecov/result_merger.rb
index 78dbcc7c..fbaf5439 100644
--- a/lib/simplecov/result_merger.rb
+++ b/lib/simplecov/result_merger.rb
@@ -82,7 +82,7 @@ def within_merge_timeout?(result)
       def merge_coverage(results)
         results = results.compact
 
-        return nil if results.size.zero?
+        return nil if results.empty?
         return results.first if results.size == 1
 
         parsed_results = results.map(&:original_result)