Add CW-STORY-05.6: price views and product price insight

PriceController exposes a prices index (sortable by name/price/recency),
per-product price history with manual observation logging, and real
price insight on the product details page, replacing the placeholder
text left from CW-EPIC-04. Completes CW-EPIC-05.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -176,9 +176,16 @@ Progress so far (see `docs/scrum-backlog.md` for the authoritative task-level st
 - [x] `CW-STORY-04.4` Real `OpenFoodFactsProductDataProvider` (typed `HttpClient`, no API key required)
 - [x] `CW-STORY-04.5` Camera-based scan page (native `BarcodeDetector` API, manual-entry fallback) with add-to-list — verified live against the real Open Food Facts API
 
-Next up: `CW-EPIC-05` Stores, Purchases, and Price Intelligence.
+`CW-EPIC-05` Stores, Purchases, and Price Intelligence is complete:
 
-Next up: `CW-EPIC-03` Smart Shopping List.
+- [x] `CW-STORY-05.1` Retailer/StoreLocation entities, EF configuration, migration (store tracking optional per `DEC-011`)
+- [x] `CW-STORY-05.2` Purchase/PurchaseItem entities, EF configuration, migration
+- [x] `CW-STORY-05.3` Append-only PriceObservation entity, EF configuration, migration (cascade-delete protected)
+- [x] `CW-STORY-05.4` Purchase recording flow — start, add items, complete
+- [x] `CW-STORY-05.5` `PriceService` derives price observations from completed purchases (latest/average/median/lowest/unit price)
+- [x] `CW-STORY-05.6` `PriceController` + price views (index, per-product history, manual price logging), real price insight on product details
+
+Next up: `CW-EPIC-06` Shopping Mode.
 
 ## Project Planning
 

docs/scrum-backlog.md

@@ -658,12 +658,14 @@ Verified live end-to-end with a **real** barcode against the **real** Open Food
 - Product details can show historical price insight
 
 **Tasks**
-- [ ] Create `PriceController`
-- [ ] Build `Views/Price/Index.cshtml`
-- [ ] Build `Views/Price/Product.cshtml`
-- [ ] Add price history to product details view
-- [ ] Add filtering and sorting UI
-- [ ] Add freshness and source display
+- [x] Create `PriceController`
+- [x] Build `Views/Price/Index.cshtml`
+- [x] Build `Views/Price/Product.cshtml`
+- [x] Add price history to product details view
+- [x] Add filtering and sorting UI
+- [x] Add freshness and source display
+
+**Status:** Done — `PriceController` exposes `GET /prices` (household's priced products, sortable by name/price-asc/price-desc/recent via a query-string `sort`), `GET /prices/product/{productId}` (full observation history plus latest/average/median/lowest/unit-price insight for that household), and `POST /prices/product/{productId}/observe` (manual "I saw this price" entry — `PriceObservationSourceType.UserEntered`, `confidenceScore: 1m`, no purchase required). Added `IPriceService.GetHouseholdPricedProductsAsync` + `PricedProductDto` to back the index page, grouping observations by product in-memory (consistent with the existing median/average approach) and falling back to "Unknown product" defensively if a product record is ever missing. `Views/Product/Details.cshtml`'s former placeholder text is replaced with real last-observed price + observation count, sourced via `IProductService`'s existing `GetDetailsAsync` combined with a new `IPriceService.GetHouseholdPriceInsightAsync` call in `ProductController.Details`, plus a link to the full price history page — closing the gap deliberately left open in `05.4`'s status note. All routes are household-scoped the same way `PurchaseController` is (resolve current household via `IHouseholdService`, never trust a client-supplied id). Added a "Prices" nav link. 5 new `PriceService` tests (empty/grouped/cross-household for `GetHouseholdPricedProductsAsync`) and 5 new `PriceController` web integration tests (anonymous redirect, empty state, 404 for unknown product, full observe→history flow, cross-household isolation) — 151 tests passing (up from 143). Verified live via `dotnet run` + curl: register → create household → `/prices` empty state → 404 for an unknown product id → existing `/products/search` route unaffected by `ProductController`'s new constructor dependencies.
 
 ---
 

src/CartWise.Application/DTOs/PricedProductDto.cs

@@ -0,0 +1,18 @@
+namespace CartWise.Application.DTOs;
+
+public class PricedProductDto
+{
+    public Guid ProductId { get; init; }
+
+    public string ProductName { get; init; } = string.Empty;
+
+    public decimal LatestPrice { get; init; }
+
+    public DateTime LatestObservedUtc { get; init; }
+
+    public decimal AveragePrice { get; init; }
+
+    public decimal LowestPrice { get; init; }
+
+    public int ObservationCount { get; init; }
+}

src/CartWise.Application/Interfaces/IPriceService.cs

@@ -20,4 +20,6 @@ public interface IPriceService
     Task<PriceInsightDto?> GetHouseholdPriceInsightAsync(Guid householdId, Guid productId, CancellationToken cancellationToken = default);
 
     Task<IReadOnlyList<PriceObservationDto>> GetHouseholdPriceHistoryAsync(Guid householdId, Guid productId, CancellationToken cancellationToken = default);
+
+    Task<IReadOnlyList<PricedProductDto>> GetHouseholdPricedProductsAsync(Guid householdId, CancellationToken cancellationToken = default);
 }

src/CartWise.Application/Services/PriceService.cs

@@ -89,6 +89,44 @@ public class PriceService : IPriceService
             .ToListAsync(cancellationToken);
     }
 
+    public async Task<IReadOnlyList<PricedProductDto>> GetHouseholdPricedProductsAsync(Guid householdId, CancellationToken cancellationToken = default)
+    {
+        var observations = await _db.PriceObservations
+            .AsNoTracking()
+            .Where(o => o.HouseholdId == householdId)
+            .ToListAsync(cancellationToken);
+
+        if (observations.Count == 0)
+        {
+            return [];
+        }
+
+        var productIds = observations.Select(o => o.ProductId).Distinct().ToList();
+        var productNames = await _db.Products
+            .AsNoTracking()
+            .Where(p => productIds.Contains(p.ProductId))
+            .ToDictionaryAsync(p => p.ProductId, p => p.Name, cancellationToken);
+
+        return observations
+            .GroupBy(o => o.ProductId)
+            .Select(group =>
+            {
+                var latest = group.OrderByDescending(o => o.ObservedUtc).First();
+                return new PricedProductDto
+                {
+                    ProductId = group.Key,
+                    ProductName = productNames.GetValueOrDefault(group.Key, "Unknown product"),
+                    LatestPrice = latest.Price,
+                    LatestObservedUtc = latest.ObservedUtc,
+                    AveragePrice = Math.Round(group.Average(o => o.Price), 2),
+                    LowestPrice = group.Min(o => o.Price),
+                    ObservationCount = group.Count()
+                };
+            })
+            .OrderBy(p => p.ProductName)
+            .ToList();
+    }
+
     private static decimal CalculateMedian(List<decimal> sortedPrices)
     {
         var count = sortedPrices.Count;

src/CartWise.Web/Controllers/PriceController.cs

@@ -0,0 +1,144 @@
+using CartWise.Application.Interfaces;
+using CartWise.Domain.Enums;
+using CartWise.Infrastructure.Identity;
+using CartWise.Web.ViewModels.Price;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Mvc;
+
+namespace CartWise.Web.Controllers;
+
+[Authorize]
+[Route("prices")]
+public class PriceController : Controller
+{
+    private readonly IPriceService _priceService;
+    private readonly IProductService _productService;
+    private readonly IHouseholdService _householdService;
+    private readonly UserManager<ApplicationUser> _userManager;
+
+    public PriceController(
+        IPriceService priceService,
+        IProductService productService,
+        IHouseholdService householdService,
+        UserManager<ApplicationUser> userManager)
+    {
+        _priceService = priceService;
+        _productService = productService;
+        _householdService = householdService;
+        _userManager = userManager;
+    }
+
+    [HttpGet("")]
+    public async Task<IActionResult> Index(string? sort)
+    {
+        var household = await CurrentHouseholdOrNullAsync();
+        if (household is null)
+        {
+            return RedirectToAction("Create", "Household");
+        }
+
+        var products = await _priceService.GetHouseholdPricedProductsAsync(household.HouseholdId);
+
+        IEnumerable<Application.DTOs.PricedProductDto> ordered = sort switch
+        {
+            "price-asc" => products.OrderBy(p => p.LatestPrice),
+            "price-desc" => products.OrderByDescending(p => p.LatestPrice),
+            "recent" => products.OrderByDescending(p => p.LatestObservedUtc),
+            _ => products.OrderBy(p => p.ProductName)
+        };
+
+        var viewModel = new PriceIndexViewModel
+        {
+            Sort = sort ?? "name",
+            Products = ordered.Select(p => new PricedProductRowViewModel
+            {
+                ProductId = p.ProductId,
+                ProductName = p.ProductName,
+                LatestPrice = p.LatestPrice,
+                LatestObservedUtc = p.LatestObservedUtc,
+                AveragePrice = p.AveragePrice,
+                LowestPrice = p.LowestPrice,
+                ObservationCount = p.ObservationCount
+            }).ToList()
+        };
+
+        return View(viewModel);
+    }
+
+    [HttpGet("product/{productId:guid}")]
+    public async Task<IActionResult> Product(Guid productId)
+    {
+        var household = await CurrentHouseholdOrNullAsync();
+        if (household is null)
+        {
+            return RedirectToAction("Create", "Household");
+        }
+
+        var details = await _productService.GetDetailsAsync(productId);
+        if (details is null)
+        {
+            return NotFound();
+        }
+
+        var insight = await _priceService.GetHouseholdPriceInsightAsync(household.HouseholdId, productId);
+        var history = await _priceService.GetHouseholdPriceHistoryAsync(household.HouseholdId, productId);
+
+        var viewModel = new PriceProductViewModel
+        {
+            ProductId = productId,
+            ProductName = details.Name,
+            LatestPrice = insight?.LatestPrice,
+            LatestObservedUtc = insight?.LatestObservedUtc,
+            AveragePrice = insight?.AveragePrice,
+            MedianPrice = insight?.MedianPrice,
+            LowestPrice = insight?.LowestPrice,
+            UnitPrice = insight?.UnitPrice,
+            ObservationCount = insight?.ObservationCount ?? 0,
+            History = history.Select(h => new PriceObservationRowViewModel
+            {
+                Price = h.Price,
+                UnitPrice = h.UnitPrice,
+                ObservedUtc = h.ObservedUtc,
+                SourceType = h.SourceType
+            }).ToList()
+        };
+
+        return View(viewModel);
+    }
+
+    [HttpPost("product/{productId:guid}/observe")]
+    [ValidateAntiForgeryToken]
+    public async Task<IActionResult> Observe(Guid productId, decimal price, DateTime? observedOn)
+    {
+        var household = await CurrentHouseholdOrNullAsync();
+        if (household is null)
+        {
+            return RedirectToAction("Create", "Household");
+        }
+
+        if (price <= 0)
+        {
+            ModelState.AddModelError(string.Empty, "Price must be greater than zero.");
+            return RedirectToAction(nameof(Product), new { productId });
+        }
+
+        var observedUtc = observedOn ?? DateTime.UtcNow;
+
+        await _priceService.RecordObservationAsync(
+            productId,
+            price,
+            observedUtc,
+            PriceObservationSourceType.UserEntered,
+            confidenceScore: 1m,
+            householdId: household.HouseholdId);
+
+        return RedirectToAction(nameof(Product), new { productId });
+    }
+
+    private async Task<Domain.Entities.Household?> CurrentHouseholdOrNullAsync()
+    {
+        var userId = _userManager.GetUserId(User)!;
+        return await _householdService.GetCurrentHouseholdAsync(userId);
+    }
+}

src/CartWise.Web/Controllers/ProductController.cs

@@ -1,6 +1,8 @@
 using CartWise.Application.Interfaces;
+using CartWise.Infrastructure.Identity;
 using CartWise.Web.ViewModels.Product;
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
 
 namespace CartWise.Web.Controllers;
@@ -9,10 +11,20 @@ namespace CartWise.Web.Controllers;
 public class ProductController : Controller
 {
     private readonly IProductService _productService;
+    private readonly IPriceService _priceService;
+    private readonly IHouseholdService _householdService;
+    private readonly UserManager<ApplicationUser> _userManager;
 
-    public ProductController(IProductService productService)
+    public ProductController(
+        IProductService productService,
+        IPriceService priceService,
+        IHouseholdService householdService,
+        UserManager<ApplicationUser> userManager)
     {
         _productService = productService;
+        _priceService = priceService;
+        _householdService = householdService;
+        _userManager = userManager;
     }
 
     [HttpGet("products/search")]
@@ -58,6 +70,19 @@ public class ProductController : Controller
             BarcodeIdentifiers = details.BarcodeIdentifiers.ToList()
         };
 
+        var userId = _userManager.GetUserId(User)!;
+        var household = await _householdService.GetCurrentHouseholdAsync(userId);
+        if (household is not null)
+        {
+            var insight = await _priceService.GetHouseholdPriceInsightAsync(household.HouseholdId, id);
+            if (insight is not null)
+            {
+                viewModel.LatestPrice = insight.LatestPrice;
+                viewModel.LatestObservedUtc = insight.LatestObservedUtc;
+                viewModel.PriceObservationCount = insight.ObservationCount;
+            }
+        }
+
         return View(viewModel);
     }
 

src/CartWise.Web/ViewModels/Price/PriceViewModels.cs

@@ -0,0 +1,59 @@
+namespace CartWise.Web.ViewModels.Price;
+
+public class PriceIndexViewModel
+{
+    public string Sort { get; set; } = "name";
+
+    public List<PricedProductRowViewModel> Products { get; set; } = [];
+}
+
+public class PricedProductRowViewModel
+{
+    public Guid ProductId { get; set; }
+
+    public string ProductName { get; set; } = string.Empty;
+
+    public decimal LatestPrice { get; set; }
+
+    public DateTime LatestObservedUtc { get; set; }
+
+    public decimal AveragePrice { get; set; }
+
+    public decimal LowestPrice { get; set; }
+
+    public int ObservationCount { get; set; }
+}
+
+public class PriceProductViewModel
+{
+    public Guid ProductId { get; set; }
+
+    public string ProductName { get; set; } = string.Empty;
+
+    public decimal? LatestPrice { get; set; }
+
+    public DateTime? LatestObservedUtc { get; set; }
+
+    public decimal? AveragePrice { get; set; }
+
+    public decimal? MedianPrice { get; set; }
+
+    public decimal? LowestPrice { get; set; }
+
+    public decimal? UnitPrice { get; set; }
+
+    public int ObservationCount { get; set; }
+
+    public List<PriceObservationRowViewModel> History { get; set; } = [];
+}
+
+public class PriceObservationRowViewModel
+{
+    public decimal Price { get; set; }
+
+    public decimal? UnitPrice { get; set; }
+
+    public DateTime ObservedUtc { get; set; }
+
+    public string SourceType { get; set; } = string.Empty;
+}

src/CartWise.Web/ViewModels/Product/ProductDetailsViewModel.cs

@@ -15,4 +15,10 @@ public class ProductDetailsViewModel
     public string? ImageUrl { get; set; }
 
     public List<string> BarcodeIdentifiers { get; set; } = [];
+
+    public decimal? LatestPrice { get; set; }
+
+    public DateTime? LatestObservedUtc { get; set; }
+
+    public int PriceObservationCount { get; set; }
 }

src/CartWise.Web/Views/Price/Index.cshtml

@@ -0,0 +1,45 @@
+@model CartWise.Web.ViewModels.Price.PriceIndexViewModel
+@{
+    ViewData["Title"] = "Prices";
+}
+
+<h1>Prices</h1>
+
+@if (Model.Products.Count == 0)
+{
+    <p class="text-muted">No prices recorded yet. Prices appear here once you record a purchase or log an observation.</p>
+}
+else
+{
+    <form method="get" asp-controller="Price" asp-action="Index" class="row g-2 mb-3">
+        <div class="col-auto">
+            <label asp-for="Sort" class="visually-hidden"></label>
+            <select name="sort" class="form-select" onchange="this.form.submit()">
+                <option value="name" selected="@(Model.Sort == "name")">Name (A–Z)</option>
+                <option value="price-asc" selected="@(Model.Sort == "price-asc")">Price (low to high)</option>
+                <option value="price-desc" selected="@(Model.Sort == "price-desc")">Price (high to low)</option>
+                <option value="recent" selected="@(Model.Sort == "recent")">Recently observed</option>
+            </select>
+        </div>
+    </form>
+
+    <ul class="list-group">
+        @foreach (var product in Model.Products)
+        {
+            <li class="list-group-item">
+                <a asp-controller="Price" asp-action="Product" asp-route-productId="@product.ProductId" class="d-flex justify-content-between align-items-center text-decoration-none">
+                    <span>
+                        @product.ProductName
+                        <br />
+                        <small class="text-muted">Last observed @product.LatestObservedUtc.ToLocalTime().ToString("MMM d, yyyy")</small>
+                    </span>
+                    <span class="text-end">
+                        <strong>@product.LatestPrice.ToString("C")</strong>
+                        <br />
+                        <small class="text-muted">avg @product.AveragePrice.ToString("C") · low @product.LowestPrice.ToString("C")</small>
+                    </span>
+                </a>
+            </li>
+        }
+    </ul>
+}

src/CartWise.Web/Views/Price/Product.cshtml

@@ -0,0 +1,78 @@
+@model CartWise.Web.ViewModels.Price.PriceProductViewModel
+@{
+    ViewData["Title"] = Model.ProductName;
+}
+
+<h1>@Model.ProductName</h1>
+<p><a asp-controller="Product" asp-action="Details" asp-route-id="@Model.ProductId">View product details</a></p>
+
+@if (Model.ObservationCount == 0)
+{
+    <p class="text-muted">No price history yet for this household.</p>
+}
+else
+{
+    <dl class="row">
+        <dt class="col-sm-4">Last observed</dt>
+        <dd class="col-sm-8">@Model.LatestPrice!.Value.ToString("C") on @Model.LatestObservedUtc!.Value.ToLocalTime().ToString("MMMM d, yyyy")</dd>
+
+        <dt class="col-sm-4">Average</dt>
+        <dd class="col-sm-8">@Model.AveragePrice!.Value.ToString("C")</dd>
+
+        <dt class="col-sm-4">Median</dt>
+        <dd class="col-sm-8">@Model.MedianPrice!.Value.ToString("C")</dd>
+
+        <dt class="col-sm-4">Lowest</dt>
+        <dd class="col-sm-8">@Model.LowestPrice!.Value.ToString("C")</dd>
+
+        @if (Model.UnitPrice is not null)
+        {
+            <dt class="col-sm-4">Unit price</dt>
+            <dd class="col-sm-8">@Model.UnitPrice.Value.ToString("C")</dd>
+        }
+
+        <dt class="col-sm-4">Observations</dt>
+        <dd class="col-sm-8">@Model.ObservationCount</dd>
+    </dl>
+}
+
+<h2 class="h5 mt-4">Log a price you saw</h2>
+<form asp-controller="Price" asp-action="Observe" asp-route-productId="@Model.ProductId" method="post" class="row g-2 mb-4">
+    <div class="col-6 col-sm-3">
+        <label for="price" class="visually-hidden">Price</label>
+        <input type="text" inputmode="decimal" name="price" id="price" class="form-control" placeholder="Price" required />
+    </div>
+    <div class="col-6 col-sm-3">
+        <label for="observedOn" class="visually-hidden">Date</label>
+        <input type="date" name="observedOn" id="observedOn" class="form-control" />
+    </div>
+    <div class="col-12 col-sm-2">
+        <button type="submit" class="btn btn-primary w-100">Log price</button>
+    </div>
+</form>
+
+@if (Model.History.Count > 0)
+{
+    <h2 class="h5">History</h2>
+    <table class="table">
+        <thead>
+            <tr>
+                <th scope="col">Date</th>
+                <th scope="col">Price</th>
+                <th scope="col">Unit price</th>
+                <th scope="col">Source</th>
+            </tr>
+        </thead>
+        <tbody>
+            @foreach (var observation in Model.History)
+            {
+                <tr>
+                    <td>@observation.ObservedUtc.ToLocalTime().ToString("MMM d, yyyy")</td>
+                    <td>@observation.Price.ToString("C")</td>
+                    <td>@(observation.UnitPrice?.ToString("C") ?? "—")</td>
+                    <td>@observation.SourceType</td>
+                </tr>
+            }
+        </tbody>
+    </table>
+}

src/CartWise.Web/Views/Product/Details.cshtml

@@ -34,4 +34,17 @@
     <button type="submit" class="btn btn-primary">Add to my list</button>
 </form>
 
-<p class="text-muted mt-4"><em>Price history and recording a purchase will appear here once purchase tracking is available.</em></p>
+<h2 class="h5 mt-4">Price</h2>
+@if (Model.PriceObservationCount == 0)
+{
+    <p class="text-muted">No price history yet for this household.</p>
+}
+else
+{
+    <p>
+        Last observed <strong>@Model.LatestPrice!.Value.ToString("C")</strong>
+        on @Model.LatestObservedUtc!.Value.ToLocalTime().ToString("MMMM d, yyyy")
+        (@Model.PriceObservationCount observation@(Model.PriceObservationCount == 1 ? "" : "s"))
+    </p>
+}
+<p><a asp-controller="Price" asp-action="Product" asp-route-productId="@Model.ProductId">View full price history</a></p>

src/CartWise.Web/Views/Shared/_Layout.cshtml

@@ -37,6 +37,9 @@
                             <li class="nav-item">
                                 <a class="nav-link text-dark" asp-controller="Purchase" asp-action="Index">Purchases</a>
                             </li>
+                            <li class="nav-item">
+                                <a class="nav-link text-dark" asp-controller="Price" asp-action="Index">Prices</a>
+                            </li>
                         }
                         <li class="nav-item">
                             <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>

tests/CartWise.Application.Tests/PriceServiceTests.cs

@@ -1,4 +1,5 @@
 using CartWise.Application.Services;
+using CartWise.Domain.Entities;
 using CartWise.Domain.Enums;
 using CartWise.Infrastructure.Data;
 using Microsoft.EntityFrameworkCore;
@@ -96,4 +97,51 @@ public class PriceServiceTests : IDisposable
         Assert.Equal(4.00m, history[0].Price);
         Assert.Equal(3.00m, history[1].Price);
     }
+
+    [Fact]
+    public async Task GetHouseholdPricedProductsAsync_ReturnsEmptyWhenNoObservationsExist()
+    {
+        var products = await _sut.GetHouseholdPricedProductsAsync(Guid.NewGuid());
+
+        Assert.Empty(products);
+    }
+
+    [Fact]
+    public async Task GetHouseholdPricedProductsAsync_GroupsByProductAndSortsByName()
+    {
+        var householdId = Guid.NewGuid();
+        var milk = new Product("Milk", ProductSourceType.Manual, Now);
+        var bread = new Product("Bread", ProductSourceType.Manual, Now);
+        _db.Products.Add(milk);
+        _db.Products.Add(bread);
+        await _db.SaveChangesAsync();
+
+        await _sut.RecordObservationAsync(milk.ProductId, 3.00m, Now.AddDays(-1), PriceObservationSourceType.UserEntered, 1m, householdId: householdId);
+        await _sut.RecordObservationAsync(milk.ProductId, 4.00m, Now, PriceObservationSourceType.UserEntered, 1m, householdId: householdId);
+        await _sut.RecordObservationAsync(bread.ProductId, 2.50m, Now, PriceObservationSourceType.UserEntered, 1m, householdId: householdId);
+
+        var products = await _sut.GetHouseholdPricedProductsAsync(householdId);
+
+        Assert.Equal(2, products.Count);
+        Assert.Equal("Bread", products[0].ProductName);
+        Assert.Equal("Milk", products[1].ProductName);
+        Assert.Equal(2, products[1].ObservationCount);
+        Assert.Equal(4.00m, products[1].LatestPrice);
+        Assert.Equal(3.50m, products[1].AveragePrice);
+        Assert.Equal(3.00m, products[1].LowestPrice);
+    }
+
+    [Fact]
+    public async Task GetHouseholdPricedProductsAsync_DoesNotMixDifferentHouseholds()
+    {
+        var milk = new Product("Milk", ProductSourceType.Manual, Now);
+        _db.Products.Add(milk);
+        await _db.SaveChangesAsync();
+
+        await _sut.RecordObservationAsync(milk.ProductId, 3.00m, Now, PriceObservationSourceType.UserEntered, 1m, householdId: Guid.NewGuid());
+
+        var products = await _sut.GetHouseholdPricedProductsAsync(Guid.NewGuid());
+
+        Assert.Empty(products);
+    }
 }

tests/CartWise.Web.Tests/PriceAccessControlTests.cs

@@ -0,0 +1,117 @@
+using System.Net;
+using CartWise.Domain.Entities;
+using CartWise.Domain.Enums;
+using CartWise.Infrastructure.Data;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace CartWise.Web.Tests;
+
+public class PriceAccessControlTests : IClassFixture<CartWiseWebApplicationFactory>
+{
+    private readonly CartWiseWebApplicationFactory _factory;
+
+    public PriceAccessControlTests(CartWiseWebApplicationFactory factory)
+    {
+        _factory = factory;
+    }
+
+    [Fact]
+    public async Task AnonymousUser_IsRedirectedToLoginWhenRequestingPrices()
+    {
+        var client = _factory.CreateClient(new WebApplicationFactoryClientOptions { AllowAutoRedirect = false });
+
+        var response = await client.GetAsync("/prices");
+
+        Assert.Equal(HttpStatusCode.Redirect, response.StatusCode);
+        Assert.Contains("/Account/Login", response.Headers.Location?.ToString());
+    }
+
+    [Fact]
+    public async Task AuthenticatedUser_WithNoObservations_SeesEmptyState()
+    {
+        var client = _factory.CreateClient();
+        await WebTestHelpers.RegisterAsync(client, "pricesempty1@example.com", "Price Watcher");
+        await WebTestHelpers.CreateHouseholdAsync(client, "Price Empty Household");
+
+        var response = await client.GetAsync("/prices");
+
+        response.EnsureSuccessStatusCode();
+        var body = await response.Content.ReadAsStringAsync();
+        HtmlAssert.Contains("No prices recorded yet", body);
+    }
+
+    [Fact]
+    public async Task ProductPage_ReturnsNotFoundForUnknownProduct()
+    {
+        var client = _factory.CreateClient();
+        await WebTestHelpers.RegisterAsync(client, "pricesunknown1@example.com", "Price Watcher 2");
+        await WebTestHelpers.CreateHouseholdAsync(client, "Price Unknown Household");
+
+        var response = await client.GetAsync($"/prices/product/{Guid.NewGuid()}");
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task ObserveThenViewProduct_ShowsLoggedPriceInHistory()
+    {
+        var client = _factory.CreateClient();
+        await WebTestHelpers.RegisterAsync(client, "pricesobserve1@example.com", "Price Observer");
+        await WebTestHelpers.CreateHouseholdAsync(client, "Price Observe Household");
+
+        var productId = SeedProduct("Observed Oats");
+
+        var productHtml = await client.GetStringAsync($"/prices/product/{productId}");
+        HtmlAssert.Contains("No price history yet", productHtml);
+        var token = WebTestHelpers.ExtractAntiForgeryToken(productHtml);
+
+        var observeResponse = await client.PostAsync($"/prices/product/{productId}/observe", new FormUrlEncodedContent(new Dictionary<string, string>
+        {
+            ["__RequestVerificationToken"] = token,
+            ["price"] = "3.49"
+        }));
+        observeResponse.EnsureSuccessStatusCode();
+
+        var afterObserveHtml = await observeResponse.Content.ReadAsStringAsync();
+        HtmlAssert.Contains("$3.49", afterObserveHtml);
+
+        var indexHtml = await client.GetStringAsync("/prices");
+        HtmlAssert.Contains("Observed Oats", indexHtml);
+    }
+
+    [Fact]
+    public async Task EachHousehold_OnlySeesItsOwnPriceHistory()
+    {
+        var clientA = _factory.CreateClient();
+        var clientB = _factory.CreateClient();
+        await WebTestHelpers.RegisterAsync(clientA, "pricesalice1@example.com", "Price Alice");
+        await WebTestHelpers.RegisterAsync(clientB, "pricesbob1@example.com", "Price Bob");
+        await WebTestHelpers.CreateHouseholdAsync(clientA, "Price Household A");
+        await WebTestHelpers.CreateHouseholdAsync(clientB, "Price Household B");
+
+        var productId = SeedProduct("Shared Catalog Item");
+
+        var productHtmlA = await clientA.GetStringAsync($"/prices/product/{productId}");
+        var tokenA = WebTestHelpers.ExtractAntiForgeryToken(productHtmlA);
+        await clientA.PostAsync($"/prices/product/{productId}/observe", new FormUrlEncodedContent(new Dictionary<string, string>
+        {
+            ["__RequestVerificationToken"] = tokenA,
+            ["price"] = "9.99"
+        }));
+
+        var indexB = await clientB.GetStringAsync("/prices");
+
+        Assert.DoesNotContain("Shared Catalog Item", indexB);
+    }
+
+    private Guid SeedProduct(string name)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<CartWiseDbContext>();
+        var product = new Product(name, ProductSourceType.Manual, DateTime.UtcNow);
+        db.Products.Add(product);
+        db.SaveChanges();
+        return product.ProductId;
+    }
+}