fix: use Because() for custom TUnit messages and add global.json for dotnet test support

Co-authored-by: ascott18 <5017521+ascott18@users.noreply.github.com>

Author: Copilot

CHANGELOG.md

@@ -1,5 +1,8 @@
 # 6.2.1
 
+## Template Changes
+- Template test projects now use TUnit instead of xUnit.
+
 # 6.2.0
 - Add COA0014 analyzer to avoid incorrect usage of `NoAutoInclude`.
 - Added `DefaultOrderByAttribute.Suppress` property to prevent properties from being used as fallback ordering.

templates/Coalesce.Vue.Template/content/Coalesce.Starter.Vue.Data.Test/Utilities/AssertionExtensions.cs

@@ -29,7 +29,7 @@ public static async Task AssertSuccess(this ApiResult result, string? message =
     {
         await Assert.That(result.WasSuccessful)
             .IsTrue()
-            .WithMessage(() => result.Message ?? "");
+            .Because(result.Message ?? "");
         await Assert.That(result.Message).IsEqualTo(message);
     }
 
@@ -40,7 +40,7 @@ public static async Task<T> AssertSuccess<T>(this ItemResult<T> result)
     {
         await Assert.That(result.WasSuccessful)
             .IsTrue()
-            .WithMessage(() => result.Message ?? "");
+            .Because(result.Message ?? "");
         await Assert.That(result.Message).IsNull();
         return result.Object ?? throw new ArgumentException("Successful result unexpectedly returned null object");
     }
@@ -62,7 +62,7 @@ public static async Task AssertSuccess(this Task<ItemResult> resultTask)
         var result = await resultTask;
         await Assert.That(result.WasSuccessful)
             .IsTrue()
-            .WithMessage(() => result.Message ?? "");
+            .Because(result.Message ?? "");
     }
 
     /// <summary>

templates/Coalesce.Vue.Template/content/global.json

@@ -0,0 +1,5 @@
+{
+  "test": {
+    "runner": "Microsoft.Testing.Platform"
+  }
+}