disallow project delete when there are existing bugs

Author: chrisK00

BugLab.Business/CommandHandlers/Projects/DeleteProjectHandler.cs

@@ -1,8 +1,11 @@
 using BugLab.Business.Commands.Projects;
 using BugLab.Business.Helpers;
 using BugLab.Data;
+using BugLab.Shared.Enums;
 using MediatR;
 using Microsoft.EntityFrameworkCore;
+using System;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -22,6 +25,11 @@ public async Task<Unit> Handle(DeleteProjectCommand request, CancellationToken c
  var project = await _context.Projects.FirstOrDefaultAsync(p => p.Id == request.Id, cancellationToken);
  Guard.NotFound(project, nameof(project), request.Id);
 
+ if (await _context.Bugs.AnyAsync(b => b.ProjectId == project.Id && b.Status != BugStatus.Resolved, cancellationToken))
+ {
+ throw new InvalidOperationException("remove or resolve existing bugs before deletion");
+ }
+
  _context.Projects.Remove(project);
  await _context.SaveChangesAsync(cancellationToken);