Add twoWayBinding support and writable signal test cases

Co-authored-by: timdeschryver <[email protected]>

Author: Copilot

README.md

@@ -157,7 +157,7 @@ Angular Testing Library also supports Angular's native bindings API, which provi
 
 ```typescript
 import { render, screen } from '@testing-library/angular';
-import { inputBinding, outputBinding } from '@angular/core';
+import { inputBinding, outputBinding, twoWayBinding, signal } from '@angular/core';
 import { CounterComponent } from './counter.component';
 
 describe('Counter with Bindings API', () => {
@@ -182,6 +182,23 @@ describe('Counter with Bindings API', () => {
 
     expect(clickHandler).toHaveBeenCalledWith(1);
   });
+
+  it('should handle two-way binding with signals', async () => {
+    const counterSignal = signal(0);
+
+    await render(CounterComponent, {
+      bindings: [twoWayBinding('counter', counterSignal)],
+    });
+
+    expect(screen.getByText('Current Count: 0')).toBeVisible();
+
+    const incrementButton = screen.getByRole('button', { name: '+' });
+    fireEvent.click(incrementButton);
+
+    // Two-way binding updates the external signal
+    expect(counterSignal()).toBe(1);
+    expect(screen.getByText('Current Count: 1')).toBeVisible();
+  });
 });
 ```
 

projects/testing-library/src/lib/models.ts

@@ -317,12 +317,14 @@ export interface RenderComponentOptions<ComponentType, Q extends Queries = typeo
    * []
    *
    * @example
-   * import { inputBinding, outputBinding } from '@angular/core';
+   * import { inputBinding, outputBinding, twoWayBinding } from '@angular/core';
+   * import { signal } from '@angular/core';
    *
    * await render(AppComponent, {
    *   bindings: [
    *     inputBinding('value', () => 'test value'),
-   *     outputBinding('click', (event) => console.log(event))
+   *     outputBinding('click', (event) => console.log(event)),
+   *     twoWayBinding('name', signal('initial value'))
    *   ]
    * })
    */

projects/testing-library/tests/bindings-support.spec.ts

@@ -1,4 +1,4 @@
-import { Component, input, output, inputBinding, outputBinding } from '@angular/core';
+import { Component, input, output, inputBinding, outputBinding, twoWayBinding, signal, model } from '@angular/core';
 import { render, screen, aliasedInput } from '../src/public_api';
 
 describe('ATL Bindings API Support', () => {
@@ -17,6 +17,23 @@ describe('ATL Bindings API Support', () => {
     clicked = output<string>();
   }
 
+  @Component({
+    selector: 'atl-two-way-test',
+    template: `
+      <div data-testid="name-display">{{ name() }}</div>
+      <input data-testid="name-input" [value]="name()" (input)="name.set($any($event.target).value)" />
+      <button data-testid="update-button" (click)="updateName()">Update</button>
+    `,
+    standalone: true,
+  })
+  class TwoWayBindingTestComponent {
+    name = model<string>('default');
+
+    updateName() {
+      this.name.set('updated from component');
+    }
+  }
+
   it('should support inputBinding for regular inputs', async () => {
     await render(BindingsTestComponent, {
       bindings: [inputBinding('value', () => 'test-value'), inputBinding('greet', () => 'hi there')],
@@ -39,6 +56,49 @@ describe('ATL Bindings API Support', () => {
     expect(clickHandler).toHaveBeenCalledWith('clicked: bound-value');
   });
 
+  it('should support inputBinding with writable signal for re-rendering scenario', async () => {
+    const valueSignal = signal('initial-value');
+
+    await render(BindingsTestComponent, {
+      bindings: [inputBinding('value', valueSignal), inputBinding('greet', () => 'hi there')],
+    });
+
+    expect(screen.getByTestId('value')).toHaveTextContent('initial-value');
+    expect(screen.getByTestId('greeting')).toHaveTextContent('hi there');
+
+    // Update the signal and verify it reflects in the component
+    valueSignal.set('updated-value');
+
+    // The binding should automatically update the component
+    expect(await screen.findByText('updated-value')).toBeInTheDocument();
+  });
+
+  it('should support twoWayBinding for model signals', async () => {
+    const nameSignal = signal('initial name');
+
+    await render(TwoWayBindingTestComponent, {
+      bindings: [twoWayBinding('name', nameSignal)],
+    });
+
+    // Verify initial value
+    expect(screen.getByTestId('name-display')).toHaveTextContent('initial name');
+    expect(screen.getByTestId('name-input')).toHaveValue('initial name');
+
+    // Update from outside (signal change)
+    nameSignal.set('updated from signal');
+    expect(await screen.findByDisplayValue('updated from signal')).toBeInTheDocument();
+    expect(screen.getByTestId('name-display')).toHaveTextContent('updated from signal');
+
+    // Update from component - let's trigger change detection after the click
+    const updateButton = screen.getByTestId('update-button');
+    updateButton.click();
+
+    // Give Angular a chance to process the update and check both the signal and display
+    // The twoWayBinding should update the external signal
+    expect(await screen.findByText('updated from component')).toBeInTheDocument();
+    expect(nameSignal()).toBe('updated from component');
+  });
+
   it('should warn when mixing bindings with traditional inputs but still work', async () => {
     const consoleSpy = jest.spyOn(console, 'warn').mockImplementation();
     const clickHandler = jest.fn();