Add more shadowing tests

packages/@ember/-internals/glimmer/tests/integration/helpers/array-test.js

@@ -1,4 +1,10 @@
-import { RenderingTestCase, moduleFor, strip, runTask } from 'internal-test-helpers';
+import {
+  RenderingTestCase,
+  defineComponent,
+  moduleFor,
+  runTask,
+  strip,
+} from 'internal-test-helpers';
 
 import { set } from '@ember/object';
 
@@ -20,6 +26,21 @@ moduleFor(
       this.assertStableRerender();
     }
 
+    ['@test the array helper can be shadowed']() {
+      function array(...list) {
+        return list.map((n) => n * 2);
+      }
+
+      let First = defineComponent({ array }, `{{#each (array 1 2 3) as |n|}}[{{n}}]{{/each}}`);
+
+      let Root = defineComponent(
+        { shadowArray: array, First },
+        `{{#let shadowArray as |array|}}{{#each (array 5 10 15) as |n|}}[{{n}}]{{/each}}{{/let}}<First />`
+      );
+
+      this.renderComponent(Root, { expect: '[10][20][30][2][4][6]' });
+    }
+
     ['@test can have more than one value']() {
       this.render(strip`
       {{#let (array "Sergio" "Robert") as |people|}}

packages/@ember/-internals/glimmer/tests/integration/helpers/fn-test.js

@@ -1,6 +1,6 @@
 import { set } from '@ember/object';
 import { DEBUG } from '@glimmer/env';
-import { RenderingTestCase, moduleFor, runTask } from 'internal-test-helpers';
+import { RenderingTestCase, defineComponent, moduleFor, runTask } from 'internal-test-helpers';
 import { Component } from '../../utils/helpers';
 
 moduleFor(
@@ -22,6 +22,14 @@ moduleFor(
       });
     }
 
+    '@test fn can be shadowed'() {
+      let First = defineComponent(
+        { fn: boundFn, boundFn, id, invoke },
+        `[{{invoke (fn id 1)}}]{{#let boundFn as |fn|}}[{{invoke (fn id 2)}}{{/let}}]`
+      );
+      this.renderComponent(First, { expect: `[bound:1][bound:2]` });
+    }
+
     '@test updates when arguments change'() {
       this.render(`{{invoke (fn this.myFunc this.arg1 this.arg2)}}`, {
         myFunc(arg1, arg2) {
@@ -209,3 +217,13 @@ moduleFor(
     }
   }
 );
+
+function invoke(fn) {
+  return fn();
+}
+
+function boundFn(fn, ...args) {
+  return () => fn(...args.map((arg) => `bound:${arg}`));
+}
+
+let id = (arg) => arg;

packages/@ember/-internals/glimmer/tests/integration/helpers/get-test.js

@@ -1,4 +1,4 @@
-import { RenderingTestCase, moduleFor, runTask } from 'internal-test-helpers';
+import { RenderingTestCase, defineComponent, moduleFor, runTask } from 'internal-test-helpers';
 
 import { set, get } from '@ember/object';
 
@@ -32,6 +32,17 @@ moduleFor(
       this.assertText('[red] [red]');
     }
 
+    ['@test can be shadowed']() {
+      let get = (obj, key) => `obj.${key}=${obj[key]}`;
+      let obj = { apple: 'red', banana: 'yellow' };
+      let Root = defineComponent(
+        { get, outerGet: get, obj },
+        `[{{get obj 'apple'}}][{{#let outerGet as |get|}}{{get obj 'banana'}}{{/let}}]`
+      );
+
+      this.renderComponent(Root, { expect: '[obj.apple=red][obj.banana=yellow]' });
+    }
+
     ['@test should be able to get an object value with nested static key']() {
       this.render(
         `[{{get this.colors "apple.gala"}}] [{{if true (get this.colors "apple.gala")}}]`,

packages/@ember/-internals/glimmer/tests/integration/helpers/hash-test.js

@@ -1,4 +1,4 @@
-import { RenderingTestCase, moduleFor, runTask } from 'internal-test-helpers';
+import { RenderingTestCase, defineComponent, moduleFor, runTask } from 'internal-test-helpers';
 
 import { Component } from '../../utils/helpers';
 
@@ -17,6 +17,21 @@ moduleFor(
       this.assertText('Sergio');
     }
 
+    ['@test can be shadowed']() {
+      let hash = (obj) =>
+        Object.entries(obj)
+          .map(([key, value]) => `hash:${key}=${value}`)
+          .join(',');
+      let Root = defineComponent(
+        { hash, shadowHash: hash },
+        `({{hash apple='red' banana='yellow'}}) ({{#let shadowHash as |hash|}}{{hash apple='green'}}{{/let}})`
+      );
+
+      this.renderComponent(Root, {
+        expect: '(hash:apple=red,hash:banana=yellow) (hash:apple=green)',
+      });
+    }
+
     ['@test can have more than one key-value']() {
       this.render(
         `{{#let (hash name="Sergio" lastName="Arbeo") as |person|}}{{person.name}} {{person.lastName}}{{/let}}`

packages/internal-test-helpers/lib/test-cases/rendering.ts

@@ -1,19 +1,19 @@
-import type { EmberPrecompileOptions } from 'ember-template-compiler';
-import { compile } from 'ember-template-compiler';
-import { EventDispatcher } from '@ember/-internals/views';
 import type { Renderer } from '@ember/-internals/glimmer';
+import { _resetRenderers, helper, Helper } from '@ember/-internals/glimmer';
+import { EventDispatcher } from '@ember/-internals/views';
 import Component, { setComponentTemplate } from '@ember/component';
-import { helper, Helper, _resetRenderers } from '@ember/-internals/glimmer';
+import type { EmberPrecompileOptions } from 'ember-template-compiler';
+import { compile } from 'ember-template-compiler';
 import type Resolver from '../test-resolver';
 import { ModuleBasedResolver } from '../test-resolver';
 
-import AbstractTestCase from './abstract';
-import buildOwner from '../build-owner';
-import { runAppend, runDestroy, runTask } from '../run';
 import type { InternalFactory } from '@ember/-internals/owner';
-import type { BootOptions, EngineInstanceOptions } from '@ember/engine/instance';
-import type EngineInstance from '@ember/engine/instance';
 import templateOnly from '@ember/component/template-only';
+import type EngineInstance from '@ember/engine/instance';
+import type { BootOptions, EngineInstanceOptions } from '@ember/engine/instance';
+import buildOwner from '../build-owner';
+import { runAppend, runDestroy, runTask } from '../run';
+import AbstractTestCase from './abstract';
 
 const TextNode = window.Text;
 
@@ -172,6 +172,13 @@ export default abstract class RenderingTestCase extends AbstractTestCase {
     runAppend(this.component);
   }
 
+  renderComponent(component: object, options: { expect: string }) {
+    this.registerComponent('root', { ComponentClass: component });
+    this.render('<Root />');
+    this.assertHTML(options.expect);
+    this.assertStableRerender();
+  }
+
   rerender() {
     this.component!.rerender();
   }
@@ -195,14 +202,21 @@ export default abstract class RenderingTestCase extends AbstractTestCase {
 
   registerComponent(
     name: string,
-    { ComponentClass = Component, template = null, resolveableTemplate = null }
+    {
+      ComponentClass = Component,
+      template = null,
+      resolveableTemplate = null,
+    }: {
+      ComponentClass?: object | null;
+      template?: string | null;
+      resolveableTemplate?: string | null;
+    }
   ) {
     let { owner } = this;
 
     if (ComponentClass) {
       // We cannot set templates multiple times on a class
       if (ComponentClass === Component) {
-        // @ts-expect-error - class/instance types in TS are hard
         ComponentClass = class extends Component {};
       }