feat(api): support task deadlines

TaskTracker.Api/Controllers/TasksController.cs

@@ -52,6 +52,7 @@ public class TasksController(ITaskRepository taskRepo, ILogger<TasksController>
             Category = request.Category,
             ParentTaskId = request.ParentTaskId,
             EstimatedMinutes = request.EstimatedMinutes,
+            DueAt = request.DueAt,
             Status = WorkTaskStatus.Pending
         };
 
@@ -173,6 +174,8 @@ public class TasksController(ITaskRepository taskRepo, ILogger<TasksController>
         if (request.Description is not null) task.Description = request.Description;
         if (request.Category is not null) task.Category = request.Category;
         if (request.EstimatedMinutes.HasValue) task.EstimatedMinutes = request.EstimatedMinutes;
+        if (request.ClearDueAt) task.DueAt = null;
+        else if (request.DueAt.HasValue) task.DueAt = request.DueAt;
         if (request.ParentTaskId.HasValue)
         {
             var parent = await taskRepo.GetByIdAsync(request.ParentTaskId.Value);

TaskTracker.Tests/TaskTracker.Tests.csproj

@@ -7,6 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">
@@ -16,6 +17,8 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="..\TaskTracker.Api\TaskTracker.Api.csproj" />
     <ProjectReference Include="..\TaskTracker.Core\TaskTracker.Core.csproj" />
+    <ProjectReference Include="..\TaskTracker.Infrastructure\TaskTracker.Infrastructure.csproj" />
   </ItemGroup>
 </Project>

TaskTracker.Tests/TasksControllerDeadlineTests.cs

@@ -0,0 +1,91 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using TaskTracker.Api.Controllers;
+using TaskTracker.Core.DTOs;
+using TaskTracker.Core.Entities;
+using TaskTracker.Infrastructure.Data;
+using TaskTracker.Infrastructure.Repositories;
+using Xunit;
+
+namespace TaskTracker.Tests;
+
+public class TasksControllerDeadlineTests
+{
+    [Fact]
+    public async Task Create_copies_due_at_including_offset_to_created_task()
+    {
+        await using var db = CreateDbContext();
+        var controller = CreateController(db);
+        var dueAt = DateTimeOffset.Parse("2026-08-14T11:00:00-04:00");
+
+        var result = await controller.Create(new CreateTaskRequest { Title = "deadline", DueAt = dueAt });
+
+        var created = Assert.IsType<CreatedAtActionResult>(result);
+        var response = Assert.IsType<ApiResponse<WorkTask>>(created.Value);
+        Assert.Equal(dueAt, response.Data!.DueAt);
+    }
+
+    [Fact]
+    public async Task Update_changes_due_at_when_value_is_supplied()
+    {
+        await using var db = CreateDbContext();
+        var task = await AddTaskAsync(db, DateTimeOffset.Parse("2026-08-14T11:00:00-04:00"));
+        var controller = CreateController(db);
+        var dueAt = DateTimeOffset.Parse("2026-08-15T09:30:00+02:00");
+
+        var result = await controller.Update(task.Id, new UpdateTaskRequest { DueAt = dueAt });
+
+        var ok = Assert.IsType<OkObjectResult>(result);
+        var response = Assert.IsType<ApiResponse<WorkTask>>(ok.Value);
+        Assert.Equal(dueAt, response.Data!.DueAt);
+    }
+
+    [Fact]
+    public async Task Update_clears_due_at_only_when_clear_due_at_is_true()
+    {
+        await using var db = CreateDbContext();
+        var task = await AddTaskAsync(db, DateTimeOffset.Parse("2026-08-14T11:00:00-04:00"));
+        var controller = CreateController(db);
+
+        var result = await controller.Update(task.Id, new UpdateTaskRequest { ClearDueAt = true });
+
+        var ok = Assert.IsType<OkObjectResult>(result);
+        var response = Assert.IsType<ApiResponse<WorkTask>>(ok.Value);
+        Assert.Null(response.Data!.DueAt);
+    }
+
+    [Fact]
+    public async Task Update_with_omitted_due_at_preserves_existing_due_at()
+    {
+        await using var db = CreateDbContext();
+        var dueAt = DateTimeOffset.Parse("2026-08-14T11:00:00-04:00");
+        var task = await AddTaskAsync(db, dueAt);
+        var controller = CreateController(db);
+
+        var result = await controller.Update(task.Id, new UpdateTaskRequest { Title = "renamed" });
+
+        var ok = Assert.IsType<OkObjectResult>(result);
+        var response = Assert.IsType<ApiResponse<WorkTask>>(ok.Value);
+        Assert.Equal(dueAt, response.Data!.DueAt);
+    }
+
+    private static TaskTrackerDbContext CreateDbContext()
+    {
+        var options = new DbContextOptionsBuilder<TaskTrackerDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        return new TaskTrackerDbContext(options);
+    }
+
+    private static TasksController CreateController(TaskTrackerDbContext db) =>
+        new(new TaskRepository(db), NullLogger<TasksController>.Instance);
+
+    private static async Task<WorkTask> AddTaskAsync(TaskTrackerDbContext db, DateTimeOffset dueAt)
+    {
+        var task = new WorkTask { Title = "existing", DueAt = dueAt };
+        db.Tasks.Add(task);
+        await db.SaveChangesAsync();
+        return task;
+    }
+}