refactor IAM test for loose match

test/integration/workload_metadata_config/controls/gcloud.rb

@@ -51,17 +51,21 @@
       its(:exit_status) { should eq 0 }
       its(:stderr) { should eq '' }
 
-      let!(:iam) do
+      let(:bindings) do
         if subject.exit_status == 0
-          JSON.parse(subject.stdout)
+          JSON.parse(subject.stdout, symbolize_names: true)[:bindings]
         else
-          {}
+          []
         end
       end
       it "has expected registry roles" do
-        expect(iam['bindings']).to include(
-          {"members" => ["serviceAccount:#{service_account}"], "role" => "roles/storage.objectViewer"},
-          {"members" => ["serviceAccount:#{service_account}"], "role" => "roles/artifactregistry.reader"}
+        expect(bindings).to include(
+          members: including("serviceAccount:#{service_account}"),
+          role: "roles/storage.objectViewer",
+        )
+        expect(bindings).to include(
+          members: including("serviceAccount:#{service_account}"),
+          role: "roles/artifactregistry.reader",
         )
       end
     end