fix(learning): validate tenant question grading rules

Tiku.Infrastructure/Content/DirectContentService.cs

@@ -4,6 +4,7 @@ using Microsoft.EntityFrameworkCore;
 using Tiku.Application.Assets;
 using Tiku.Application.Catalog;
 using Tiku.Application.Content;
+using Tiku.Application.Learning;
 using Tiku.Application.QuestionBanks;
 using Tiku.Application.Security;
 using Tiku.Domain.Catalog;
@@ -50,6 +51,7 @@ public sealed class DirectContentService(
         QuestionWriteCommand command,
         CancellationToken cancellationToken = default)
     {
+        ValidateQuestionForPublication(command);
         await AssertQuestionReferencesAsync(actor.TenantId, command, cancellationToken);
         await using var transaction = dbContext.Database.CurrentTransaction is null
             ? await dbContext.Database.BeginTransactionAsync(cancellationToken)
@@ -94,6 +96,8 @@ public sealed class DirectContentService(
             throw new ContentManagementException("questionId is required.", "question_id_required");
         }
 
+        ValidateQuestionForPublication(command);
+
         var question = await dbContext.Questions.SingleOrDefaultAsync(
             item => item.TenantId == actor.TenantId && item.Id == command.QuestionId.Value,
             cancellationToken);
@@ -1496,6 +1500,27 @@ public sealed class DirectContentService(
         question.Status = Parse(command.Status, QuestionStatus.Published, "question_status_invalid");
     }
 
+    private static void ValidateQuestionForPublication(QuestionWriteCommand command)
+    {
+        var status = Parse(command.Status, QuestionStatus.Published, "question_status_invalid");
+        if (status != QuestionStatus.Published)
+        {
+            return;
+        }
+
+        var type = Normalize(command.Type) ?? "choice";
+        if (!QuestionGrader.HasValidAuthoritativeAnswer(
+                type,
+                command.CorrectOptionIndex,
+                command.CorrectOptionIndices,
+                command.AnswerText))
+        {
+            throw new ContentManagementException(
+                "Published questions require a valid authoritative answer.",
+                "question_grading_rule_invalid");
+        }
+    }
+
     private static QuestionVersion BuildQuestionVersion(
         DirectContentActor actor,
         Guid questionId,

Tiku.IntegrationTests/Api/DirectContentEndpointTests.cs

@@ -64,6 +64,26 @@ public sealed class DirectContentEndpointTests
         Assert.Equal(1, dbContext.QuestionCollections.Single(item => item.Id == collectionId).QuestionCount);
     }
 
+    [Fact]
+    public async Task Published_objective_question_requires_authoritative_answer_but_draft_does_not()
+    {
+        await using var factory = new ApiTestFactory();
+        var seed = await SeedAdminAsync(factory);
+        using var client = factory.CreateClient();
+        await LoginAsync(client, seed);
+
+        using var published = await client.PostAsJsonAsync(
+            "/api/tenant-content/questions",
+            new DirectQuestionWriteDto { Type = "choice", Content = "缺少答案", Status = "Published" });
+        using var draft = await client.PostAsJsonAsync(
+            "/api/tenant-content/questions",
+            new DirectQuestionWriteDto { Type = "choice", Content = "草稿题", Status = "Draft" });
+
+        Assert.Equal(HttpStatusCode.BadRequest, published.StatusCode);
+        Assert.Equal("question_grading_rule_invalid", await ReadProblemCodeAsync(published));
+        Assert.Equal(HttpStatusCode.OK, draft.StatusCode);
+    }
+
     [Fact]
     public async Task Tenant_admin_can_upsert_vocabulary_handbook_video_and_operations_content()
     {
@@ -128,7 +148,7 @@ public sealed class DirectContentEndpointTests
 
         var questionResponse = await client.PostAsJsonAsync(
             "/api/tenant-content/questions",
-            new DirectQuestionWriteDto { Type = "choice", Content = "题目" });
+            new DirectQuestionWriteDto { Type = "choice", Content = "题目", CorrectOptionIndex = 0 });
         var questionJson = await ReadJsonAsync(questionResponse);
         var questionId = questionJson.RootElement.GetProperty("item").GetProperty("id").GetGuid();
 
@@ -148,7 +168,7 @@ public sealed class DirectContentEndpointTests
             {
                 Items =
                 [
-                    JsonSerializer.SerializeToElement(new { type = "choice", content = "导入预览题" })
+                    JsonSerializer.SerializeToElement(new { type = "choice", content = "导入预览题", correctOptionIndex = 0 })
                 ]
             });
         var previewJson = await ReadJsonAsync(previewResponse);
@@ -160,7 +180,7 @@ public sealed class DirectContentEndpointTests
             {
                 Items =
                 [
-                    JsonSerializer.SerializeToElement(new { type = "choice", content = "导入执行题" })
+                    JsonSerializer.SerializeToElement(new { type = "choice", content = "导入执行题", correctOptionIndex = 0 })
                 ]
             });
         var executeJson = await ReadJsonAsync(executeResponse);
@@ -198,7 +218,7 @@ public sealed class DirectContentEndpointTests
                 Async = true,
                 Items =
                 [
-                    JsonSerializer.SerializeToElement(new { type = "choice", content = "异步导入题" })
+                    JsonSerializer.SerializeToElement(new { type = "choice", content = "异步导入题", correctOptionIndex = 0 })
                 ]
             });
         var queuedJob = await queueResponse.Content.ReadFromJsonAsync<BackgroundJobItem>(JsonOptions);
@@ -374,4 +394,10 @@ public sealed class DirectContentEndpointTests
         return await JsonDocument.ParseAsync(stream);
     }
 
+    private static async Task<string?> ReadProblemCodeAsync(HttpResponseMessage response)
+    {
+        using var payload = await ReadJsonAsync(response);
+        return payload.RootElement.TryGetProperty("code", out var code) ? code.GetString() : null;
+    }
+
 }