backend-test-utils: automatically stop backends after test

Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/backend-app-api/src/wiring/BackendInitializer.ts

@@ -170,7 +170,7 @@ export class BackendInitializer {
 
   async stop(): Promise<void> {
     if (!this.#started) {
-      throw new Error('Backend has not started');
+      return;
     }
     this.#started = false;
 

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

@@ -31,6 +31,8 @@ export interface TestBackendOptions<
   TServices extends any[],
   TExtensionPoints extends any[],
 > {
+  // (undocumented)
+  autoStop?: boolean;
   // (undocumented)
   extensionPoints?: readonly [
     ...{

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

@@ -32,7 +32,7 @@ describe('TestBackend', () => {
     const extensionPoint3 = createExtensionPoint<Obj>({ id: 'b3' });
     const extensionPoint4 = createExtensionPoint<Obj>({ id: 'b4' });
     const extensionPoint5 = createExtensionPoint<Obj>({ id: 'b5' });
-    const backend = await startTestBackend({
+    await startTestBackend({
       services: [
         // @ts-expect-error
         [extensionPoint1, { a: 'a' }],
@@ -59,7 +59,6 @@ describe('TestBackend', () => {
       ],
     });
     expect(1).toBe(1);
-    await backend.stop();
   });
 
   it('should start the test backend', async () => {
@@ -89,13 +88,12 @@ describe('TestBackend', () => {
       },
     });
 
-    const backend = await startTestBackend({
+    await startTestBackend({
       services: [sf],
       features: [testModule()],
     });
 
     expect(testFn).toHaveBeenCalledWith('winning');
-    await backend.stop();
   });
 
   it('should stop the test backend', async () => {
@@ -119,6 +117,7 @@ describe('TestBackend', () => {
     const backend = await startTestBackend({
       services: [],
       features: [testModule()],
+      autoStop: false,
     });
 
     expect(shutdownSpy).not.toHaveBeenCalled();

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

@@ -51,6 +51,7 @@ export interface TestBackendOptions<
     },
   ];
   features?: BackendFeature[];
+  autoStop?: boolean;
 }
 
 const defaultServiceFactories = [
@@ -59,6 +60,8 @@ const defaultServiceFactories = [
   lifecycleFactory(),
 ];
 
+const backendInstances = new Array<Backend>();
+
 /** @alpha */
 export async function startTestBackend<
   TServices extends any[],
@@ -68,6 +71,7 @@ export async function startTestBackend<
     services = [],
     extensionPoints = [],
     features = [],
+    autoStop = true,
     ...otherOptions
   } = options;
 
@@ -103,6 +107,10 @@ export async function startTestBackend<
     services: factories,
   });
 
+  if (autoStop) {
+    backendInstances.push(backend);
+  }
+
   backend.add({
     id: `---test-extension-point-registrar`,
     register(reg) {
@@ -122,3 +130,27 @@ export async function startTestBackend<
 
   return backend;
 }
+
+let registered = false;
+function registerTestHooks() {
+  if (typeof afterEach !== 'function') {
+    return;
+  }
+  if (registered) {
+    return;
+  }
+  registered = true;
+
+  afterEach(async () => {
+    for (const backend of backendInstances) {
+      try {
+        await backend.stop();
+      } catch (error) {
+        console.error(`Failed to stop backend after test, ${error}`);
+      }
+    }
+    backendInstances.length = 0;
+  });
+}
+
+registerTestHooks();