From 6e951ad36366310551b128a406187862730e16f2 Mon Sep 17 00:00:00 2001
From: Josh Joseph <jjosephttg@gmail.com>
Date: Mon, 28 Nov 2022 11:09:55 -0500
Subject: [PATCH] feat: childComponentOverrides property to override nested
 child providers (#332)

---
 projects/testing-library/src/lib/models.ts    | 25 ++++++
 .../src/lib/testing-library.ts                | 10 ++-
 projects/testing-library/tests/render.spec.ts | 81 ++++++++++++++-----
 3 files changed, 94 insertions(+), 22 deletions(-)

diff --git a/projects/testing-library/src/lib/models.ts b/projects/testing-library/src/lib/models.ts
index 953c244..1f33192 100644
--- a/projects/testing-library/src/lib/models.ts
+++ b/projects/testing-library/src/lib/models.ts
@@ -186,6 +186,26 @@ export interface RenderComponentOptions<ComponentType, Q extends Queries = typeo
    * })
    */
   componentProviders?: any[];
+  /**
+   * @description
+   * Collection of child component specified providers to override with
+   *
+   * @default
+   * []
+   *
+   * @example
+   * await render(AppComponent, {
+   *  childComponentOverrides: [
+   *    {
+   *      component: ChildOfAppComponent,
+   *      providers: [{ provide: MyService, useValue: { hello: 'world' } }]
+   *    }
+   *  ]
+   * })
+   *
+   * @experimental
+   */
+  childComponentOverrides?: ComponentOverride<any>[];
   /**
    * @description
    * A collection of imports to override a standalone component's imports with.
@@ -273,6 +293,11 @@ export interface RenderComponentOptions<ComponentType, Q extends Queries = typeo
   removeAngularAttributes?: boolean;
 }
 
+export interface ComponentOverride<T> {
+  component: Type<T>;
+  providers: any[];
+}
+
 // eslint-disable-next-line @typescript-eslint/ban-types
 export interface RenderTemplateOptions<WrapperType, Properties extends object = {}, Q extends Queries = typeof queries>
   extends RenderComponentOptions<Properties, Q> {
diff --git a/projects/testing-library/src/lib/testing-library.ts b/projects/testing-library/src/lib/testing-library.ts
index 933e982..24e2085 100644
--- a/projects/testing-library/src/lib/testing-library.ts
+++ b/projects/testing-library/src/lib/testing-library.ts
@@ -25,7 +25,7 @@ import {
   queries as dtlQueries,
 } from '@testing-library/dom';
 import type { Queries, BoundFunctions } from '@testing-library/dom';
-import { RenderComponentOptions, RenderTemplateOptions, RenderResult } from './models';
+import { RenderComponentOptions, RenderTemplateOptions, RenderResult, ComponentOverride } from './models';
 import { getConfig } from './config';
 
 const mountedFixtures = new Set<ComponentFixture<any>>();
@@ -55,6 +55,7 @@ export async function render<SutType, WrapperType = SutType>(
     wrapper = WrapperComponent as Type<WrapperType>,
     componentProperties = {},
     componentProviders = [],
+    childComponentOverrides = [],
     ɵcomponentImports: componentImports,
     excludeComponentDeclaration = false,
     routes = [],
@@ -85,6 +86,7 @@ export async function render<SutType, WrapperType = SutType>(
     schemas: [...schemas],
   });
   overrideComponentImports(sut, componentImports);
+  overrideChildComponentProviders(childComponentOverrides);
 
   await TestBed.compileComponents();
 
@@ -282,6 +284,12 @@ function overrideComponentImports<SutType>(sut: Type<SutType> | string, imports:
   }
 }
 
+function overrideChildComponentProviders(componentOverrides: ComponentOverride<any>[]) {
+  componentOverrides?.forEach(({ component, providers }) => {
+    TestBed.overrideComponent(component, { set: { providers } });
+  });
+}
+
 function hasOnChangesHook<SutType>(componentInstance: SutType): componentInstance is SutType & OnChanges {
   return (
     'ngOnChanges' in componentInstance && typeof (componentInstance as SutType & OnChanges).ngOnChanges === 'function'
diff --git a/projects/testing-library/tests/render.spec.ts b/projects/testing-library/tests/render.spec.ts
index 1faec70..4200bc9 100644
--- a/projects/testing-library/tests/render.spec.ts
+++ b/projects/testing-library/tests/render.spec.ts
@@ -7,6 +7,7 @@ import {
   SimpleChanges,
   APP_INITIALIZER,
   ApplicationInitStatus,
+  Injectable,
 } from '@angular/core';
 import { NoopAnimationsModule, BrowserAnimationsModule } from '@angular/platform-browser/animations';
 import { TestBed } from '@angular/core/testing';
@@ -19,7 +20,7 @@ import { render, fireEvent, screen } from '../src/public_api';
     <button>button</button>
   `,
 })
-class FixtureComponent { }
+class FixtureComponent {}
 
 test('creates queries and events', async () => {
   const view = await render(FixtureComponent);
@@ -50,46 +51,84 @@ describe('standalone', () => {
 
 describe('standalone with child', () => {
   @Component({
-    selector: 'child-fixture',
+    selector: 'atl-child-fixture',
     template: `<span>A child fixture</span>`,
     standalone: true,
   })
-  class ChildFixture { }
+  class ChildFixtureComponent {}
 
   @Component({
-    selector: 'child-fixture',
+    selector: 'atl-child-fixture',
     template: `<span>A mock child fixture</span>`,
     standalone: true,
   })
-  class MockChildFixture { }
+  class MockChildFixtureComponent {}
 
   @Component({
-    selector: 'parent-fixture',
+    selector: 'atl-parent-fixture',
     template: `<h1>Parent fixture</h1>
-      <div><child-fixture></child-fixture></div> `,
+      <div><atl-child-fixture></atl-child-fixture></div> `,
     standalone: true,
-    imports: [ChildFixture],
+    imports: [ChildFixtureComponent],
   })
-  class ParentFixture { }
+  class ParentFixtureComponent {}
 
   it('renders the standalone component with child', async () => {
-    await render(ParentFixture);
-    expect(screen.getByText('Parent fixture'));
-    expect(screen.getByText('A child fixture'));
+    await render(ParentFixtureComponent);
+    expect(screen.getByText('Parent fixture')).toBeInTheDocument();
+    expect(screen.getByText('A child fixture')).toBeInTheDocument();
   });
 
-  it('renders the standalone component with child', async () => {
-    await render(ParentFixture, { ɵcomponentImports: [MockChildFixture] });
-    expect(screen.getByText('Parent fixture'));
-    expect(screen.getByText('A mock child fixture'));
+  it('renders the standalone component with child given ɵcomponentImports', async () => {
+    await render(ParentFixtureComponent, { ɵcomponentImports: [MockChildFixtureComponent] });
+    expect(screen.getByText('Parent fixture')).toBeInTheDocument();
+    expect(screen.getByText('A mock child fixture')).toBeInTheDocument();
   });
 
   it('rejects render of template with componentImports set', () => {
-    const result = render(`<div><parent-fixture></parent-fixture></div>`, {
-      imports: [ParentFixture],
-      ɵcomponentImports: [MockChildFixture],
+    const view = render(`<div><atl-parent-fixture></atl-parent-fixture></div>`, {
+      imports: [ParentFixtureComponent],
+      ɵcomponentImports: [MockChildFixtureComponent],
+    });
+    return expect(view).rejects.toMatchObject({ message: /Error while rendering/ });
+  });
+});
+
+describe('childComponentOverrides', () => {
+  @Injectable()
+  class MySimpleService {
+    public value = 'real';
+  }
+
+  @Component({
+    selector: 'atl-child-fixture',
+    template: `<span>{{ simpleService.value }}</span>`,
+    standalone: true,
+    providers: [MySimpleService],
+  })
+  class NestedChildFixtureComponent {
+    public constructor(public simpleService: MySimpleService) {}
+  }
+
+  @Component({
+    selector: 'atl-parent-fixture',
+    template: `<atl-child-fixture></atl-child-fixture>`,
+    standalone: true,
+    imports: [NestedChildFixtureComponent],
+  })
+  class ParentFixtureComponent {}
+
+  it('renders with overridden child service when specified', async () => {
+    await render(ParentFixtureComponent, {
+      childComponentOverrides: [
+        {
+          component: NestedChildFixtureComponent,
+          providers: [{ provide: MySimpleService, useValue: { value: 'fake' } }],
+        },
+      ],
     });
-    return expect(result).rejects.toMatchObject({ message: /Error while rendering/ });
+
+    expect(screen.getByText('fake')).toBeInTheDocument();
   });
 });
 
@@ -117,7 +156,7 @@ describe('animationModule', () => {
   @NgModule({
     declarations: [FixtureComponent],
   })
-  class FixtureModule { }
+  class FixtureModule {}
   describe('excludeComponentDeclaration', () => {
     it('does not throw if component is declared in an imported module', async () => {
       await render(FixtureComponent, {