Add some tests

IdentityShroud.Core.Tests/Services/RealmServiceTests.cs

@@ -91,10 +91,47 @@ public class RealmServiceTests : IClassFixture<DbFixture>
         }
 
         await using var actContext = _dbFixture.CreateDbContext();
-        RealmService sut = new(actContext, _keyService);
         // Act
+        RealmService sut = new(actContext, _keyService);
         var result = await sut.FindBySlug(slug, TestContext.Current.CancellationToken);
 
+        // Verify
         Assert.Equal(name, result?.Name);
     }
+
+    [Theory]
+    [InlineData("b0423bba-2411-497b-a5b6-c5adf404b862", true)]
+    [InlineData("65ac9dba-6d43-4fa4-b57f-133ed639fbcb", false)]
+    public async Task FindById(string idString, bool shouldFind)
+    {
+        Guid id = new(idString);
+        await using (var setupContext = _dbFixture.CreateDbContext())
+        {
+            setupContext.Realms.Add(new()
+            {
+                Id = new("b0423bba-2411-497b-a5b6-c5adf404b862"),
+                Slug = "foo",
+                Name = "Foo",
+            });
+            setupContext.Realms.Add(new()
+            {
+                Id = new("d4ffc7d0-7b2c-4f02-82b9-a74610435b0d"),
+                Slug = "bar",
+                Name = "Bar",
+            });
+            
+            await setupContext.SaveChangesAsync(TestContext.Current.CancellationToken);
+        }
+
+        await using var actContext = _dbFixture.CreateDbContext();
+        // Act
+        RealmService sut = new(actContext, _keyService);
+        Realm? result = await sut.FindById(id, TestContext.Current.CancellationToken);
+
+        // Verify
+        if (shouldFind)
+            Assert.NotNull(result);
+        else 
+            Assert.Null(result);
+    }
 }