Check if repo exists before attempting to update cache info

Closes #14361

spec/workers/project_cache_worker_spec.rb

@@ -0,0 +1,27 @@
+require 'spec_helper'
+
+describe ProjectCacheWorker do
+  let(:project) { create(:project) }
+
+  subject { described_class.new }
+
+  describe '#perform' do
+    it 'updates project cache data' do
+
+      expect_any_instance_of(Repository).to receive(:size)
+      expect_any_instance_of(Repository).to receive(:commit_count)
+
+      expect_any_instance_of(Project).to receive(:update_repository_size)
+      expect_any_instance_of(Project).to receive(:update_commit_count)
+
+      subject.perform(project.id)
+    end
+
+    it 'handles missing repository data' do
+      expect_any_instance_of(Repository).to receive(:exists?).and_return(false)
+      expect_any_instance_of(Repository).not_to receive(:size)
+
+      subject.perform(project.id)
+    end
+  end
+end