v3: client can see a **link** to a domain's **router group**

* Will only show if router group is set and the routing API is not disabled

[#172547117]

Co-authored-by: Belinda Liu <bliu@pivotal.io>

Author: monamohebbi

app/presenters/v3/domain_presenter.rb

@@ -81,6 +81,13 @@ def build_links
         }
       end
 
+      routing_client = CloudController::DependencyLocator.instance.routing_api_client
+      if domain.router_group_guid && routing_client.enabled?
+        links[:router_group] = {
+          href: url_builder.build_url(path: "/routing/v1/router_groups/#{domain.router_group_guid}")
+        }
+      end
+
       links
     end
   end

spec/request/domains_spec.rb

@@ -752,27 +752,28 @@
 
       let(:domain_json) do
         {
-        guid: UUID_REGEX,
-        created_at: iso8601,
-        updated_at: iso8601,
-        name: params[:name],
-        internal: false,
-        router_group: { guid: 'some-router-guid' },
-        metadata: {
-        labels: { key: 'value' },
-        annotations: { key2: 'value2' }
-        },
-        relationships: {
-        organization: {
-          data: nil
+          guid: UUID_REGEX,
+          created_at: iso8601,
+          updated_at: iso8601,
+          name: params[:name],
+          internal: false,
+          router_group: { guid: 'some-router-guid' },
+          metadata: {
+            labels: { key: 'value' },
+            annotations: { key2: 'value2' }
           },
-        shared_organizations: {
-          data: []
-          }
-        },
-        links: {
-        self: { href: %r(#{Regexp.escape(link_prefix)}\/v3\/domains\/#{UUID_REGEX}) },
-        route_reservations: { href: %r(#{Regexp.escape(link_prefix)}\/v3/domains/#{UUID_REGEX}/route_reservations) },
+          relationships: {
+            organization: {
+              data: nil
+            },
+            shared_organizations: {
+              data: []
+            }
+          },
+          links: {
+            self: { href: %r(#{Regexp.escape(link_prefix)}/v3/domains/#{UUID_REGEX}) },
+            route_reservations: { href: %r(#{Regexp.escape(link_prefix)}/v3/domains/#{UUID_REGEX}/route_reservations) },
+            router_group: { href: %r(#{Regexp.escape(link_prefix)}/routing/v1/router_groups/some-router-guid) },
           }
         }
       end

spec/unit/presenters/v3/domain_presenter_spec.rb

@@ -172,8 +172,22 @@ module VCAP::CloudController::Presenters::V3
           expect(subject[:links][:self][:href]).to eq("#{link_prefix}/v3/domains/#{domain.guid}")
           expect(subject[:links][:organization][:href]).to eq("#{link_prefix}/v3/organizations/#{domain.owning_organization.guid}")
           expect(subject[:links][:route_reservations][:href]).to eq("#{link_prefix}/v3/domains/#{domain.guid}/route_reservations")
+          expect(subject[:links][:router_group][:href]).to eq("#{link_prefix}/routing/v1/router_groups/some-router-guid")
           expect(subject[:links][:shared_organizations][:href]).to eq("#{link_prefix}/v3/domains/#{domain.guid}/relationships/shared_organizations")
         end
+
+        context 'and the routing API is disabled' do
+          let(:routing_api_client) { instance_double(VCAP::CloudController::RoutingApi::Client) }
+
+          before do
+            allow(VCAP::CloudController::RoutingApi::Client).to receive(:new).and_return(routing_api_client)
+            allow(routing_api_client).to receive(:enabled?).and_return false
+          end
+
+          it 'does not include a link to the router group' do
+            expect(subject[:links][:router_group]).to eq(nil)
+          end
+        end
       end
     end
   end