test(03-03): add failing tests for BackendSelectionStep (WIZD-01, WIZD-04)

- Replace expect.fail stubs with real test assertions
- Tests cover card render order, card click dispatch, name validation
- RED: component file does not exist yet

src/components/wizard/BackendSelectionStep.test.tsx

@@ -2,49 +2,109 @@
 // Covers WIZD-01: card grid renders Azure Blob, Amazon S3, S3-Compatible (Azure first)
 // Covers WIZD-04: remote name field validates alphanumeric/dash/underscore
 import { describe, it, expect } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { WizardProvider } from '../../store/context';
+import { BackendSelectionStep } from './BackendSelectionStep';
+
+function renderStep() {
+  return render(
+    <WizardProvider>
+      <BackendSelectionStep />
+    </WizardProvider>
+  );
+}
 
 describe('BackendSelectionStep', () => {
   describe('WIZD-01: backend card grid', () => {
     it('renders Azure Blob Storage card', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      expect(screen.getByText('Azure Blob Storage')).toBeDefined();
     });
 
     it('renders Amazon S3 card', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      expect(screen.getByText('Amazon S3')).toBeDefined();
     });
 
     it('renders S3-Compatible card', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      expect(screen.getByText('S3-Compatible')).toBeDefined();
     });
 
     it('Azure Blob is listed before S3 in DOM order', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      const buttons = screen.getAllByRole('button');
+      // Find Azure and S3 buttons by their accessible names
+      const azureIdx = buttons.findIndex(b => b.textContent?.includes('Azure Blob Storage'));
+      const s3Idx = buttons.findIndex(b => b.textContent?.includes('Amazon S3'));
+      expect(azureIdx).toBeGreaterThanOrEqual(0);
+      expect(s3Idx).toBeGreaterThanOrEqual(0);
+      expect(azureIdx).toBeLessThan(s3Idx);
     });
 
     it('clicking a backend card dispatches SET_BACKEND_TYPE and SET_STEP', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      // Fill in a valid remote name first
+      const nameInput = screen.getByRole('textbox');
+      fireEvent.change(nameInput, { target: { value: 'my-remote' } });
+      // Click the Azure card — if navigation dispatches SET_STEP(1), component may unmount
+      // We verify no validation error appears (meaning dispatch proceeded)
+      const azureButton = screen.getAllByRole('button').find(b => b.textContent?.includes('Azure Blob Storage'))!;
+      expect(azureButton).toBeDefined();
+      fireEvent.click(azureButton);
+      // After successful navigation step fires, no validation alert should be present
+      expect(screen.queryByRole('alert')).toBeNull();
     });
   });
 
   describe('WIZD-04: remote name field', () => {
     it('renders remote name input at the top of the step', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      const nameInput = screen.getByRole('textbox');
+      expect(nameInput).toBeDefined();
+      // Verify input appears before backend cards in DOM
+      const container = nameInput.closest('form') ?? document.body;
+      const allButtons = container.querySelectorAll('button');
+      const inputPosition = Array.from(container.querySelectorAll('input, button')).indexOf(nameInput as HTMLInputElement);
+      const firstButtonPosition = Array.from(container.querySelectorAll('input, button')).indexOf(allButtons[0]);
+      expect(inputPosition).toBeLessThan(firstButtonPosition);
     });
 
     it('shows no error before first Next attempt', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      // No alert role should be present on initial render
+      expect(screen.queryByRole('alert')).toBeNull();
     });
 
     it('shows inline error after first Next attempt with invalid name', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      // Click a card without filling in name — triggers validation
+      const azureButton = screen.getAllByRole('button').find(b => b.textContent?.includes('Azure Blob Storage'))!;
+      fireEvent.click(azureButton);
+      // Error should appear
+      expect(screen.getByRole('alert')).toBeDefined();
+      expect(screen.getByText(/required/i)).toBeDefined();
     });
 
     it('accepts alphanumeric, dashes, and underscores', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      const nameInput = screen.getByRole('textbox');
+      fireEvent.change(nameInput, { target: { value: 'my-remote_01' } });
+      const azureButton = screen.getAllByRole('button').find(b => b.textContent?.includes('Azure Blob Storage'))!;
+      fireEvent.click(azureButton);
+      // Valid name — no alert should appear
+      expect(screen.queryByRole('alert')).toBeNull();
     });
 
     it('rejects names with spaces or special characters', () => {
-      expect.fail('not yet implemented');
+      renderStep();
+      const nameInput = screen.getByRole('textbox');
+      fireEvent.change(nameInput, { target: { value: 'my remote!' } });
+      const azureButton = screen.getAllByRole('button').find(b => b.textContent?.includes('Azure Blob Storage'))!;
+      fireEvent.click(azureButton);
+      // Invalid name — alert should appear
+      expect(screen.getByRole('alert')).toBeDefined();
+      expect(screen.getByText(/letters, numbers, dashes/i)).toBeDefined();
     });
   });
 });