diff --git a/GerbilManager.Tests/CmsTests.cs b/GerbilManager.Tests/CmsTests.cs
new file mode 100644
index 0000000..037b65a
--- /dev/null
+++ b/GerbilManager.Tests/CmsTests.cs
@@ -0,0 +1,83 @@
+using System.Net;
+using System.Net.Http.Json;
+using System.Text.Json;
+
+namespace GerbilManager.Tests;
+
+/// <summary>WEB-0: CMS snapshot shape, Abgabetiere auto-resolution from ForSale, block reorder.</summary>
+public class CmsTests : IClassFixture<ApiFactory>
+{
+    private readonly HttpClient _client;
+    public CmsTests(ApiFactory factory) => _client = factory.CreateClient();
+
+    [Fact]
+    public async Task Snapshot_has_site_nav_and_six_seeded_pages()
+    {
+        var doc = JsonDocument.Parse(await _client.GetStringAsync("/api/site-snapshot"));
+        var root = doc.RootElement;
+
+        Assert.Equal("de", root.GetProperty("site").GetProperty("defaultLocale").GetString());
+        var nav = root.GetProperty("site").GetProperty("navOrder").EnumerateArray().Select(x => x.GetString()).ToList();
+        Assert.Equal(new[] { "start", "ueber-die-zucht", "abgabetiere", "abgabebedingungen", "farben-genetik", "kontakt" }, nav);
+
+        var pages = root.GetProperty("pages").EnumerateArray().ToList();
+        Assert.Equal(6, pages.Count);
+        // abgabetiere page carries an AbgabetiereList block with a resolved (possibly empty) animals array
+        var abg = pages.Single(p => p.GetProperty("slug").GetString() == "abgabetiere");
+        var listBlock = abg.GetProperty("blocks").EnumerateArray()
+            .Single(b => b.GetProperty("type").GetString() == "AbgabetiereList");
+        Assert.Equal("auto", listBlock.GetProperty("data").GetProperty("mode").GetString());
+        Assert.Equal(JsonValueKind.Array, listBlock.GetProperty("data").GetProperty("animals").ValueKind);
+    }
+
+    [Fact]
+    public async Task Abgabetiere_resolves_ForSale_animals_with_becken_group()
+    {
+        // a Becken + a ForSale gerbil in it
+        var encResp = await _client.PostAsJsonAsync("/enclosures", new { name = "Verkaufsbecken" });
+        var encId = JsonDocument.Parse(await encResp.Content.ReadAsStringAsync()).RootElement.GetProperty("id").GetString();
+        await _client.PostAsJsonAsync("/gerbils", new { name = "Verkaufsmaus", gender = "female", status = "ForSale", enclosureId = encId });
+        // a non-ForSale gerbil must NOT appear
+        await _client.PostAsJsonAsync("/gerbils", new { name = "Bleibtmaus", gender = "male", status = "Active" });
+
+        var doc = JsonDocument.Parse(await _client.GetStringAsync("/api/site-snapshot"));
+        var animals = doc.RootElement.GetProperty("pages").EnumerateArray()
+            .Single(p => p.GetProperty("slug").GetString() == "abgabetiere")
+            .GetProperty("blocks").EnumerateArray()
+            .Single(b => b.GetProperty("type").GetString() == "AbgabetiereList")
+            .GetProperty("data").GetProperty("animals").EnumerateArray().ToList();
+
+        var sale = animals.SingleOrDefault(a => a.GetProperty("name").GetString() == "Verkaufsmaus");
+        Assert.Equal(JsonValueKind.Object, sale.ValueKind);
+        Assert.Equal("Verkaufsbecken", sale.GetProperty("group").GetString());
+        Assert.Equal(JsonValueKind.Array, sale.GetProperty("photos").ValueKind);
+        Assert.DoesNotContain(animals, a => a.GetProperty("name").GetString() == "Bleibtmaus");
+    }
+
+    [Fact]
+    public async Task Block_crud_and_reorder()
+    {
+        // create a page + two blocks
+        var pageResp = await _client.PostAsJsonAsync("/api/pages", new { slug = "test-page", title = "Testseite" });
+        Assert.Equal(HttpStatusCode.Created, pageResp.StatusCode);
+        var pageId = JsonDocument.Parse(await pageResp.Content.ReadAsStringAsync()).RootElement.GetProperty("id").GetString();
+
+        async Task<Guid> AddBlock(string type, object data) =>
+            JsonDocument.Parse(await (await _client.PostAsJsonAsync($"/api/pages/{pageId}/blocks", new { type, data }))
+                .Content.ReadAsStringAsync()).RootElement.GetProperty("id").GetGuid();
+
+        var b1 = await AddBlock("Heading", new { text = "Erstes", level = 2 });
+        var b2 = await AddBlock("RichText", new { markdown = "**hallo**" });
+
+        // reorder: b2 before b1
+        var reorder = await _client.PutAsJsonAsync($"/api/pages/{pageId}/blocks/order", new { blockIds = new[] { b2, b1 } });
+        Assert.Equal(HttpStatusCode.NoContent, reorder.StatusCode);
+
+        var blocks = JsonDocument.Parse(await _client.GetStringAsync("/api/pages/test-page"))
+            .RootElement.GetProperty("blocks").EnumerateArray().ToList();
+        Assert.Equal(b2.ToString(), blocks[0].GetProperty("id").GetString());
+        Assert.Equal(b1.ToString(), blocks[1].GetProperty("id").GetString());
+        // RichText markdown round-trips inside data
+        Assert.Equal("**hallo**", blocks[0].GetProperty("data").GetProperty("markdown").GetString());
+    }
+}