Add admin zone specs

#475

spec/requests/admin/dns/zones/destroy_spec.rb

@@ -0,0 +1,18 @@
+require 'rails_helper'
+
+RSpec.describe 'admin zone destroy' do
+  let!(:zone) { create(:zone) }
+
+  before :example do
+    sign_in_to_admin_area
+  end
+
+  it 'deletes zone' do
+    expect { delete admin_zone_path(zone) }.to change { DNS::Zone.count }.from(1).to(0)
+  end
+
+  it 'redirects to :index' do
+    delete admin_zone_path(zone)
+    expect(response).to redirect_to admin_zones_url
+  end
+end