Detach captured backend and profile values

internal/backend/registry_test.go

@@ -22,16 +22,13 @@ func TestEffectiveRegistryOwnsDefinitionsAndCapacityPolicies(t *testing.T) {
 			Kind: &authenticationKind, Endpoint: &authenticationEndpoint,
 		},
 	}
-	registry, err := backend.NewEffectiveRegistry(map[string]domain.Backend{
+	registry := backend.NewEffectiveRegistry(map[string]domain.Backend{
 		" local.v1 ": {
 			Endpoint: "https://backend.example/v1", ExtraParams: params,
 			ConcurrencyLimit: 2, QueueCapacity: 3,
 			SmokeTests: smokeTests,
 		},
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
 	params["nested"].(map[string]any)["enabled"] = false
 	defaultProfile = "mutated-profile"
 	reachabilityEndpoint = "https://mutated.example/ready"
@@ -79,10 +76,7 @@ func TestEffectiveRegistryOwnsDefinitionsAndCapacityPolicies(t *testing.T) {
 }
 
 func TestEffectiveRegistryMissingBackend(t *testing.T) {
-	registry, err := backend.NewEffectiveRegistry(nil)
-	if err != nil {
-		t.Fatal(err)
-	}
+	registry := backend.NewEffectiveRegistry(nil)
 	if _, err := registry.GetBackend("missing"); !errors.Is(err, backend.ErrBackendNotFound) {
 		t.Fatalf("missing backend error = %v", err)
 	}