fix(MockBuilder): respects initial config of declarations #3265

libs/ng-mocks/src/lib/mock-builder/mock-builder.promise.ts

@@ -216,7 +216,9 @@ export class MockBuilderPromise implements IMockBuilder {
   }
 
   private setConfigDef(def: any, config: any): void {
-    this.configDef.set(def, config ?? this.configDefault);
+    if (config || !this.configDef.has(def)) {
+      this.configDef.set(def, config ?? this.configDefault);
+    }
   }
 
   private setDefValue(def: any, mock: any): void {

tests/issue-3265/test.spec.ts

@@ -0,0 +1,43 @@
+import { Injectable } from '@angular/core';
+
+import { MockBuilder, MockRender, ngMocks } from 'ng-mocks';
+
+@Injectable()
+class SomeService {
+  someMethod(x: string) {
+    return x;
+  }
+}
+
+@Injectable()
+class ServiceToTest {
+  constructor(public someService: SomeService) {}
+
+  foo(x: string) {
+    return this.someService.someMethod(x);
+  }
+}
+
+// @see https://github.com/help-me-mom/ng-mocks/issues/3265
+describe('issue-3265', () => {
+  beforeEach(() =>
+    MockBuilder(ServiceToTest, SomeService).mock(SomeService, {
+      someMethod:
+        typeof jest === 'undefined'
+          ? jasmine.createSpy().and.callFake((x: string) => x)
+          : // in case of jest
+            jest.fn((x: string) => x),
+    }),
+  );
+
+  it('should do something', () => {
+    const serviceToTest =
+      MockRender(ServiceToTest).point.componentInstance;
+    const someServiceSpy = ngMocks.get(SomeService);
+
+    const result = serviceToTest.foo('hello world');
+
+    expect(result).toBe('hello world');
+    expect(someServiceSpy.someMethod).toHaveBeenCalled();
+  });
+});