diff --git a/changelogs/unreleased/50564-chat-service-refactoring.yml b/changelogs/unreleased/50564-chat-service-refactoring.yml
new file mode 100644
index 00000000000..aec5e8fab0a
--- /dev/null
+++ b/changelogs/unreleased/50564-chat-service-refactoring.yml
@@ -0,0 +1,5 @@
+---
+title: Use sample data for push event when no commits created
+merge_request: 21440
+author: Takuya Noguchi
+type: fixed
diff --git a/lib/gitlab/data_builder/push.rb b/lib/gitlab/data_builder/push.rb
index c169c8fe135..b498f113859 100644
--- a/lib/gitlab/data_builder/push.rb
+++ b/lib/gitlab/data_builder/push.rb
@@ -97,11 +97,15 @@ module Gitlab
         }
       end
 
-      # This method provide a sample data generated with
+      # This method provides a sample data generated with
       # existing project and commits to test webhooks
       def build_sample(project, user)
+        # Use sample data if repo has no commit
+        # (expect the case of test service configuration settings)
+        return sample_data if project.empty_repo?
+
         ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}#{project.default_branch}"
-        commits = project.repository.commits(project.default_branch.to_s, limit: 3) rescue []
+        commits = project.repository.commits(project.default_branch.to_s, limit: 3)
 
         build(project, user, commits.last&.id, commits.first&.id, ref, commits)
       end
diff --git a/spec/models/project_services/chat_notification_service_spec.rb b/spec/models/project_services/chat_notification_service_spec.rb
index 3aa1039d8bf..46713df77da 100644
--- a/spec/models/project_services/chat_notification_service_spec.rb
+++ b/spec/models/project_services/chat_notification_service_spec.rb
@@ -26,4 +26,54 @@ describe ChatNotificationService do
       end
     end
   end
+
+  describe '#execute' do
+    let(:chat_service) { described_class.new }
+    let(:user) { create(:user) }
+    let(:project) { create(:project, :repository) }
+    let(:webhook_url) { 'https://example.gitlab.com/' }
+
+    before do
+      allow(chat_service).to receive_messages(
+        project: project,
+        project_id: project.id,
+        service_hook: true,
+        webhook: webhook_url
+      )
+
+      WebMock.stub_request(:post, webhook_url)
+
+      subject.active = true
+    end
+
+    context 'with a repository' do
+      it 'returns true' do
+        subject.project = project
+        data = Gitlab::DataBuilder::Push.build_sample(project, user)
+
+        expect(Slack::Notifier).to receive(:new)
+         .with(webhook_url, {})
+         .and_return(
+           double(:slack_service).as_null_object
+         )
+
+        expect(chat_service.execute(data)).to be true
+      end
+    end
+
+    context 'with an empty repository' do
+      it 'returns true' do
+        subject.project = create(:project, :empty_repo)
+        data = Gitlab::DataBuilder::Push.build_sample(subject.project, user)
+
+        expect(Slack::Notifier).to receive(:new)
+         .with(webhook_url, {})
+         .and_return(
+           double(:slack_service).as_null_object
+         )
+
+        expect(chat_service.execute(data)).to be true
+      end
+    end
+  end
 end