backend-test-utils: remove callback form features from startTestBackend

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/smooth-pianos-argue.md

@@ -2,4 +2,4 @@
 '@backstage/backend-test-utils': patch
 ---
 
-Updated `ServiceFactoryTester` to only accept plain service factory objects, no longer supporting the callback form. This lines up with the changes to `@backstage/backend-plugin-api` and should not require any code changes.
+Updated `startTestBackend` and `ServiceFactoryTester` to only accept plain service factory or backend feature objects, no longer supporting the callback form. This lines up with the changes to `@backstage/backend-plugin-api` and should not require any code changes.

packages/backend-test-utils/api-report.md

@@ -430,9 +430,8 @@ export interface TestBackendOptions<TExtensionPoints extends any[]> {
   // (undocumented)
   features?: Array<
     | BackendFeature
-    | (() => BackendFeature)
     | Promise<{
-        default: BackendFeature | (() => BackendFeature);
+        default: BackendFeature;
       }>
   >;
 }

packages/backend-test-utils/src/next/wiring/TestBackend.ts

@@ -48,11 +48,7 @@ export interface TestBackendOptions<TExtensionPoints extends any[]> {
       ];
     },
   ];
-  features?: Array<
-    | BackendFeature
-    | (() => BackendFeature)
-    | Promise<{ default: BackendFeature | (() => BackendFeature) }>
-  >;
+  features?: Array<BackendFeature | Promise<{ default: BackendFeature }>>;
 }
 
 /** @public */