Refactor repeated test host setup

JobTrackerApi.Tests/TestSupport/TestHostFactory.cs

@@ -0,0 +1,50 @@
+using JobTrackerApi.Data;
+using JobTrackerApi.Models;
+using JobTrackerApi.Services;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using Moq;
+
+namespace JobTrackerApi.Tests.TestSupport;
+
+public static class TestHostFactory
+{
+    // Keep the EF-backed controller tests on the same minimal setup so they fail for product
+    // reasons, not because each file drifted into a slightly different fake host configuration.
+    public static JobTrackerContext CreateInMemoryDb(string userId = "user-1")
+    {
+        var options = new DbContextOptionsBuilder<JobTrackerContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        var currentUser = new Mock<ICurrentUserService>();
+        currentUser.SetupGet(service => service.UserId).Returns(userId);
+        return new JobTrackerContext(options, currentUser.Object);
+    }
+
+    public static Mock<UserManager<ApplicationUser>> CreateUserManager(ApplicationUser? lookupUser = null)
+    {
+        var store = new Mock<IUserStore<ApplicationUser>>();
+        var manager = new Mock<UserManager<ApplicationUser>>(
+            store.Object,
+            Options.Create(new IdentityOptions()),
+            new PasswordHasher<ApplicationUser>(),
+            Array.Empty<IUserValidator<ApplicationUser>>(),
+            Array.Empty<IPasswordValidator<ApplicationUser>>(),
+            new UpperInvariantLookupNormalizer(),
+            new IdentityErrorDescriber(),
+            null!,
+            new NullLogger<UserManager<ApplicationUser>>()
+        );
+
+        if (lookupUser is not null)
+        {
+            manager
+                .Setup(x => x.FindByIdAsync(It.IsAny<string>()))
+                .ReturnsAsync((string id) => lookupUser.Id == id ? lookupUser : null);
+        }
+
+        return manager;
+    }
+}