feat(planner): add SwapSuggestionList component for J4 swap context

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/planner/SwapSuggestionList.test.ts

@@ -0,0 +1,88 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen } from '@testing-library/svelte';
+import { userEvent } from '@testing-library/user-event';
+import SwapSuggestionList from './SwapSuggestionList.svelte';
+
+const recipes = [
+	{ id: 'r1', name: 'Quick carbonara', effort: 'easy', cookTimeMin: 20 },
+	{ id: 'r2', name: 'Chicken stir-fry', effort: 'easy', cookTimeMin: 25 },
+	{ id: 'r3', name: 'Mushroom risotto', effort: 'medium', cookTimeMin: 50 }
+];
+
+const baseProps = {
+	replacingName: 'Tomato pasta',
+	replacingMeta: '45 min · Easy',
+	recipes,
+	currentWeekRecipeIds: new Set<string>(),
+	onpick: vi.fn()
+};
+
+describe('SwapSuggestionList', () => {
+	it('renders the Replacing banner', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.getByText(/Replacing/i)).toBeTruthy();
+	});
+
+	it('renders old meal name with strikethrough', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		const struck = screen.getByTestId('replacing-name');
+		expect(struck.textContent).toContain('Tomato pasta');
+		expect(getComputedStyle(struck).textDecoration || struck.style.textDecoration).toContain('line-through');
+	});
+
+	it('renders the easiest-first eyebrow label', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.getByText(/easiest first/i)).toBeTruthy();
+	});
+
+	it('renders all recipe names', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.getByText('Quick carbonara')).toBeTruthy();
+		expect(screen.getByText('Chicken stir-fry')).toBeTruthy();
+		expect(screen.getByText('Mushroom risotto')).toBeTruthy();
+	});
+
+	it('clicking Pick calls onpick with recipeId and name', async () => {
+		const onpick = vi.fn();
+		const user = userEvent.setup();
+		render(SwapSuggestionList, { props: { ...baseProps, onpick } });
+		const buttons = screen.getAllByRole('button', { name: /Pick/i });
+		await user.click(buttons[0]);
+		expect(onpick).toHaveBeenCalledWith('r1', 'Quick carbonara');
+	});
+
+	it('shows already-planned warning for recipes in currentWeekRecipeIds', () => {
+		render(SwapSuggestionList, {
+			props: { ...baseProps, currentWeekRecipeIds: new Set(['r2']) }
+		});
+		expect(screen.getByTestId('already-planned-r2')).toBeTruthy();
+	});
+
+	it('does not show already-planned warning for recipes not in currentWeekRecipeIds', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.queryByTestId('already-planned-r1')).toBeNull();
+	});
+
+	it('shows empty state when no recipes', () => {
+		render(SwapSuggestionList, { props: { ...baseProps, recipes: [] } });
+		expect(screen.getByTestId('swap-empty-state')).toBeTruthy();
+	});
+
+	it('renders optional Cancel button when oncancel provided', () => {
+		render(SwapSuggestionList, { props: { ...baseProps, oncancel: vi.fn() } });
+		expect(screen.getByRole('button', { name: /Cancel/i })).toBeTruthy();
+	});
+
+	it('does not render Cancel button when oncancel not provided', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.queryByRole('button', { name: /Cancel/i })).toBeNull();
+	});
+
+	it('clicking Cancel calls oncancel', async () => {
+		const oncancel = vi.fn();
+		const user = userEvent.setup();
+		render(SwapSuggestionList, { props: { ...baseProps, oncancel } });
+		await user.click(screen.getByRole('button', { name: /Cancel/i }));
+		expect(oncancel).toHaveBeenCalledOnce();
+	});
+});