Refactor repeated test host setup

JobTrackerApi.Tests/GmailControllerTests.cs

@@ -3,6 +3,7 @@ using JobTrackerApi.Controllers;
 using JobTrackerApi.Data;
 using JobTrackerApi.Models;
 using JobTrackerApi.Services;
+using JobTrackerApi.Tests.TestSupport;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
@@ -520,12 +521,7 @@ public sealed class GmailControllerTests
 
     private static JobTrackerContext CreateDb()
     {
-        var options = new DbContextOptionsBuilder<JobTrackerContext>()
-            .UseInMemoryDatabase(Guid.NewGuid().ToString())
-            .Options;
-        var currentUser = new Mock<ICurrentUserService>();
-        currentUser.SetupGet(service => service.UserId).Returns("user-1");
-        return new JobTrackerContext(options, currentUser.Object);
+        return TestHostFactory.CreateInMemoryDb();
     }
 
     private static Microsoft.Extensions.Configuration.IConfiguration BuildConfig()