Initial curated itworx-knowledge-hub source from 3b1751d0d9dee551aa6994eee0093704dc334817

tests/backend/ItWorx.KnowledgeHub.IntegrationTests/Knowledge/BacklinksTests.cs

@@ -0,0 +1,72 @@
+using System.Net.Http.Json;
+using ItWorx.KnowledgeHub.Contracts.Knowledge;
+using ItWorx.KnowledgeHub.IntegrationTests.Infrastructure;
+
+namespace ItWorx.KnowledgeHub.IntegrationTests.Knowledge;
+
+/// <summary>Backlinks ("what links here") update correctly after link, title, slug and
+/// tree changes (docs/27-acceptance-matrix.md, M3-A03).</summary>
+[Collection(PostgresTestGroup.Name)]
+public sealed class BacklinksTests(PostgresContainerFixture postgres) : OwnerSetupTestBase(postgres)
+{
+    [Fact]
+    public async Task A_page_appears_in_another_pages_backlinks_once_it_links_there_and_disappears_once_the_link_is_removed()
+    {
+        using var client = Factory.CreateClient();
+        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);
+
+        var targetResponse = await SetupHelper.PostWithCsrfAsync(
+            client, "/api/v1/pages", new CreatePageRequest(null, "Doelpagina", "WikiPage", "De doelpagina.", null));
+        var target = await targetResponse.Content.ReadFromJsonAsync<PageDetail>();
+        Assert.NotNull(target);
+
+        var sourceResponse = await SetupHelper.PostWithCsrfAsync(
+            client, "/api/v1/pages", new CreatePageRequest(null, "Bronpagina", "WikiPage", "Zie [[Doelpagina]].", null));
+        var source = await sourceResponse.Content.ReadFromJsonAsync<PageDetail>();
+        Assert.NotNull(source);
+
+        var backlinks = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
+        Assert.NotNull(backlinks);
+        Assert.Contains(backlinks.Items, entry => entry.Id == source.Id);
+
+        // Renaming the target must not break the already-resolved backlink relationship.
+        var renamedTargetResponse = await SetupHelper.PutWithCsrfAsync(
+            client,
+            $"/api/v1/pages/{target.Id}",
+            new UpdatePageRequest("Doelpagina (hernoemd)", "De doelpagina.", "WikiPage", "Active", null),
+            target.ETag);
+        Assert.True(renamedTargetResponse.IsSuccessStatusCode);
+
+        var backlinksAfterRename = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
+        Assert.NotNull(backlinksAfterRename);
+        Assert.Contains(backlinksAfterRename.Items, entry => entry.Id == source.Id);
+
+        // Removing the link from the source page removes the backlink.
+        var unlinkedSourceResponse = await SetupHelper.PutWithCsrfAsync(
+            client,
+            $"/api/v1/pages/{source.Id}",
+            new UpdatePageRequest("Bronpagina", "Geen verwijzing meer.", "WikiPage", "Active", null),
+            source.ETag);
+        Assert.True(unlinkedSourceResponse.IsSuccessStatusCode);
+
+        var backlinksAfterUnlink = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{target.Id}/backlinks");
+        Assert.NotNull(backlinksAfterUnlink);
+        Assert.DoesNotContain(backlinksAfterUnlink.Items, entry => entry.Id == source.Id);
+    }
+
+    [Fact]
+    public async Task A_page_with_no_incoming_links_has_an_empty_backlinks_list()
+    {
+        using var client = Factory.CreateClient();
+        await SetupHelper.LoginAsync(client, OwnerEmail, OwnerPassword);
+
+        var response = await SetupHelper.PostWithCsrfAsync(
+            client, "/api/v1/pages", new CreatePageRequest(null, "Eenzame pagina", "WikiPage", "Niemand linkt hierheen.", null));
+        var page = await response.Content.ReadFromJsonAsync<PageDetail>();
+        Assert.NotNull(page);
+
+        var backlinks = await client.GetFromJsonAsync<BacklinksResponse>($"/api/v1/pages/{page.Id}/backlinks");
+        Assert.NotNull(backlinks);
+        Assert.Empty(backlinks.Items);
+    }
+}