refactor(ivy): check metadata presence before compiling Type in R3TestBed (#34204)

Prior to this commit, there was no check in R3TestBed to verify that metadata is resolved using a given Type. That leads to some cryptic error messages (when TestBed tries to compile a Type without having metadata) in case TestBed override functions receive unexpected Types (for example a Directive is used in `TestBed.overrideComponent` call). This commit adds the necessary checks to verify metadata presence before TestBed tries to (re)compile a Type.

PR Close #34204

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, 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, ɵɵdefineNgModule as defineNgModule, 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';
@@ -715,6 +715,36 @@ describe('TestBed', () => {
             expect(fixture.nativeElement.innerHTML).toEqual('<outer><inner>Inner</inner></outer>');
           });
 
+  onlyInIvy('Ivy-specific errors').describe('checking types before compiling them', () => {
+    @Directive({
+      selector: 'my-dir',
+    })
+    class MyDir {
+    }
+
+    @NgModule()
+    class MyModule {
+    }
+
+    // [decorator, type, overrideFn]
+    const cases: [string, Type<any>, string][] = [
+      ['Component', MyDir, 'overrideComponent'],
+      ['NgModule', MyDir, 'overrideModule'],
+      ['Pipe', MyModule, 'overridePipe'],
+      ['Directive', MyModule, 'overrideDirective'],
+    ];
+    cases.forEach(([decorator, type, overrideFn]) => {
+      it(`should throw an error in case invalid type is used in ${overrideFn} function`, () => {
+        TestBed.configureTestingModule({declarations: [MyDir]});
+        expect(() => {
+          (TestBed as any)[overrideFn](type, {});
+          TestBed.createComponent(type);
+        }).toThrowError(new RegExp(`class doesn't have @${decorator} decorator`, 'g'));
+      });
+    });
+  });
+
+
   onlyInIvy('TestBed should handle AOT pre-compiled Components')
       .describe('AOT pre-compiled components', () => {
         /**

packages/core/testing/src/r3_test_bed_compiler.ts

@@ -129,10 +129,10 @@ export class R3TestBedCompiler {
     this.resolvers.module.addOverride(ngModule, override);
     const metadata = this.resolvers.module.resolve(ngModule);
     if (metadata === null) {
-      throw new Error(`${ngModule.name} is not an @NgModule or is missing metadata`);
+      throw invalidTypeError(ngModule.name, 'NgModule');
     }
 
-    this.recompileNgModule(ngModule);
+    this.recompileNgModule(ngModule, metadata);
 
     // At this point, the module has a valid module def (ɵmod), but the override may have introduced
     // new declarations or imported modules. Ingest any possible new types and add them to the
@@ -306,7 +306,10 @@ export class R3TestBedCompiler {
     let needsAsyncResources = false;
     this.pendingComponents.forEach(declaration => {
       needsAsyncResources = needsAsyncResources || isComponentDefPendingResolution(declaration);
-      const metadata = this.resolvers.component.resolve(declaration) !;
+      const metadata = this.resolvers.component.resolve(declaration);
+      if (metadata === null) {
+        throw invalidTypeError(declaration.name, 'Component');
+      }
       this.maybeStoreNgDef(NG_COMP_DEF, declaration);
       compileComponent(declaration, metadata);
     });
@@ -314,13 +317,19 @@ export class R3TestBedCompiler {
 
     this.pendingDirectives.forEach(declaration => {
       const metadata = this.resolvers.directive.resolve(declaration);
+      if (metadata === null) {
+        throw invalidTypeError(declaration.name, 'Directive');
+      }
       this.maybeStoreNgDef(NG_DIR_DEF, declaration);
       compileDirective(declaration, metadata);
     });
     this.pendingDirectives.clear();
 
     this.pendingPipes.forEach(declaration => {
-      const metadata = this.resolvers.pipe.resolve(declaration) !;
+      const metadata = this.resolvers.pipe.resolve(declaration);
+      if (metadata === null) {
+        throw invalidTypeError(declaration.name, 'Pipe');
+      }
       this.maybeStoreNgDef(NG_PIPE_DEF, declaration);
       compilePipe(declaration, metadata);
     });
@@ -434,11 +443,7 @@ export class R3TestBedCompiler {
     }
   }
 
-  private recompileNgModule(ngModule: Type<any>): void {
+  private recompileNgModule(ngModule: Type<any>, metadata: NgModule): void {
-    const metadata = this.resolvers.module.resolve(ngModule);
-    if (metadata === null) {
-      throw new Error(`Unable to resolve metadata for NgModule: ${ngModule.name}`);
-    }
     // Cache the initial ngModuleDef as it will be overwritten.
     this.maybeStoreNgDef(NG_MOD_DEF, ngModule);
     this.maybeStoreNgDef(NG_INJ_DEF, ngModule);
@@ -751,6 +756,10 @@ function forEachRight<T>(values: T[], fn: (value: T, idx: number) => void): void
   }
 }
 
+function invalidTypeError(name: string, expectedType: string): Error {
+  return new Error(`${name} class doesn't have @${expectedType} decorator or is missing metadata.`);
+}
+
 class R3TestCompiler implements Compiler {
   constructor(private testBed: R3TestBedCompiler) {}