Add tests for default initial branch name setting

spec/views/admin/application_settings/repository.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'admin/application_settings/repository.html.haml' do
+  let(:app_settings) { build(:application_setting) }
+  let(:user) { create(:admin) }
+
+  before do
+    assign(:application_setting, app_settings)
+    allow(view).to receive(:current_user).and_return(user)
+  end
+
+  describe 'default initial branch name' do
+    context 'when the feature flag is disabled' do
+      before do
+        stub_feature_flags(global_default_branch_name: false)
+      end
+
+      it 'does not show the setting section' do
+        render
+
+        expect(rendered).not_to have_css("#js-default-branch-name")
+      end
+    end
+
+    context 'when the feature flag is enabled' do
+      before do
+        stub_feature_flags(global_default_branch_name: true)
+      end
+
+      it 'has the setting section' do
+        render
+
+        expect(rendered).to have_css("#js-default-branch-name")
+      end
+
+      it 'renders the correct setting section content' do
+        render
+
+        expect(rendered).to have_content("Default initial branch name")
+        expect(rendered).to have_content("Set the default name of the initial branch when creating new repositories through the user interface.")
+      end
+    end
+  end
+end