Increment only a single trace bytes counter

lib/gitlab/ci/trace/metrics.rb

@@ -18,7 +18,7 @@ module Gitlab
         end
 
         def increment_trace_bytes(size)
-          self.class.trace_bytes.increment(by: size.to_i)
+          self.class.trace_bytes.increment({}, size.to_i)
         end
 
         def self.trace_operations

spec/lib/gitlab/ci/trace/metrics_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Ci::Trace::Metrics do
+  describe '#increment_trace_bytes' do
+    context 'when incrementing by more than one' do
+      it 'increments a single counter' do
+        subject.increment_trace_bytes(10)
+        subject.increment_trace_bytes(20)
+        subject.increment_trace_bytes(30)
+
+        expect(described_class.trace_bytes.get).to eq 60
+        expect(described_class.trace_bytes.values.count).to eq 1
+      end
+    end
+  end
+end