fix(ivy): TestBed not unwrapping imports array function when overriding provider (#34629)

Fixes an error that is thrown when a provider is overridden in `TestBed`, if the module definition of one of the imported modules uses a function for the `imports` that is set via `setNgModuleScope`. The problem was that we have a `for...of` loop that assumes that the imports are an array, but they can also be a function. This was handled correctly in other places, but this one was missed.

Note that the above-mentioned error is only thrown at runtime when the code is transpiled to es6. In es5 TS generates a call to a helper that handles the error silently so the attached unit test only fails in es6.

Fixes #34623.

PR Close #34629

packages/core/test/test_bed_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Compiler, Component, Directive, ErrorHandler, Inject, Injectable, InjectionToken, Injector, Input, ModuleWithProviders, NgModule, Optional, Pipe, Type, ViewChild, ɵsetClassMetadata as setClassMetadata, ɵɵdefineComponent as defineComponent, ɵɵdefineNgModule as defineNgModule, ɵɵtext as text} from '@angular/core';
+import {Compiler, Component, Directive, ErrorHandler, Inject, Injectable, InjectionToken, Injector, Input, ModuleWithProviders, NgModule, Optional, Pipe, Type, ViewChild, ɵsetClassMetadata as setClassMetadata, ɵɵdefineComponent as defineComponent, ɵɵdefineInjector as defineInjector, ɵɵdefineNgModule as defineNgModule, ɵɵsetNgModuleScope as setNgModuleScope, ɵɵtext as text} from '@angular/core';
 import {TestBed, getTestBed} from '@angular/core/testing/src/test_bed';
 import {By} from '@angular/platform-browser';
 import {expect} from '@angular/platform-browser/testing/src/matchers';
@@ -1002,4 +1002,44 @@ describe('TestBed', () => {
           expect(TestBed.inject(Service)).toBeDefined();
         });
       });
+
+  onlyInIvy('uses Ivy-specific compiler output')
+      .it('should handle provider overrides when module imports are provided as a function', () => {
+        class InjectedString {
+          value?: string;
+        }
+
+        @Component({template: '{{injectedString.value}}'})
+        class AppComponent {
+          constructor(public injectedString: InjectedString) {}
+        }
+
+        @NgModule({})
+        class DependencyModule {
+        }
+
+        // We need to write the compiler output manually here,
+        // because it depends on code generated by ngcc.
+        class TestingModule {
+          static ɵmod = defineNgModule({type: TestingModule});
+          static ɵinj =
+              defineInjector({factory: () => new TestingModule(), imports: [DependencyModule]});
+        }
+        setNgModuleScope(TestingModule, {imports: () => [DependencyModule]});
+
+        TestBed
+            .configureTestingModule({
+              imports: [TestingModule],
+              declarations: [AppComponent],
+              providers: [{provide: InjectedString, useValue: {value: 'initial'}}],
+            })
+            .compileComponents();
+
+        TestBed.overrideProvider(InjectedString, {useValue: {value: 'changed'}})
+            .compileComponents();
+
+        const fixture = TestBed.createComponent(AppComponent);
+        fixture.detectChanges();
+        expect(fixture !.nativeElement.textContent).toContain('changed');
+      });
 });

packages/core/testing/src/r3_test_bed_compiler.ts

@@ -413,8 +413,9 @@ export class R3TestBedCompiler {
       }
 
       // Apply provider overrides to imported modules recursively
-      const moduleDef: any = (moduleType as any)[NG_MOD_DEF];
-      for (const importedModule of moduleDef.imports) {
+      const moduleDef = (moduleType as any)[NG_MOD_DEF];
+      const imports = maybeUnwrapFn(moduleDef.imports);
+      for (const importedModule of imports) {
         this.applyProviderOverridesToModule(importedModule);
       }
       // Also override the providers on any ModuleWithProviders imports since those don't appear in