Mitigate EF Core internal race condition on first-time model materialization with [ClassInitialize] warm-up.

Author: RyanLamansky

SqlServerSimulator.Tests.EFCore/AssemblyHooks.cs

@@ -19,4 +19,21 @@ public static async Task HotPath(TestContext context)
         using var dbContext = new TestDbContext(1, 2);
         _ = await dbContext.Rows.Select(x => x.Id).FirstOrDefaultAsync(context.CancellationToken);
     }
+
+    /// <summary>
+    /// Drives one EF Core <see cref="DbContext"/> subtype's model build +
+    /// runtime-initializer to completion on a single thread, so subsequent
+    /// parallel test methods that share the type don't race on EF Core's
+    /// internal model cache. <c>GetRelationalModel</c> is the call that
+    /// raises "model must be finalized and its runtime dependencies must be
+    /// initialized" when another thread observes a half-initialized cached
+    /// model; invoking it here guarantees the cache entry is fully wired
+    /// before parallel use begins. Call from each test class's
+    /// <c>[ClassInitialize]</c> when the class declares its own context type.
+    /// </summary>
+    internal static void WarmModel(Func<DbContext> factory)
+    {
+        using var context = factory();
+        _ = context.Model.GetRelationalModel();
+    }
 }

SqlServerSimulator.Tests.EFCore/EFCoreConcurrencyTokens.cs

@@ -20,6 +20,9 @@ public class EFCoreConcurrencyTokens
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new InventoryContext(new Simulation()));
+
     private sealed class Item
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreDate.cs

@@ -13,6 +13,9 @@ public class EFCoreDate
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new AdapterTestDbContext(new Simulation()));
+
     [TestMethod]
     public void Insert_DateOnly_RoundTrips()
     {

SqlServerSimulator.Tests.EFCore/EFCoreEagerSplitQueries.cs

@@ -16,6 +16,9 @@ public class EFCoreEagerSplitQueries
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new BlogContext(new Simulation()));
+
     private sealed class Blog
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreExecuteUpdateDelete.cs

@@ -19,6 +19,9 @@ public class EFCoreExecuteUpdateDelete
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new UserContext(new Simulation()));
+
     private sealed class User
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreForeignKey.cs

@@ -16,6 +16,9 @@ public sealed class EFCoreForeignKey
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new LibraryContext(new Simulation()));
+
     private sealed class Author
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreHiLo.cs

@@ -16,6 +16,9 @@ public sealed class EFCoreHiLo
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new HiLoDbContext(new Simulation()));
+
     private class HiLoEntity
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreInheritanceTpc.cs

@@ -17,6 +17,9 @@ public class EFCoreInheritanceTpc
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new PetContext(new Simulation()));
+
     private abstract class Pet
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreInheritanceTph.cs

@@ -18,6 +18,9 @@ public class EFCoreInheritanceTph
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new PetContext(new Simulation()));
+
     private abstract class Pet
     {
         public int Id { get; set; }

SqlServerSimulator.Tests.EFCore/EFCoreInheritanceTpt.cs

@@ -19,6 +19,9 @@ public class EFCoreInheritanceTpt
 {
     public TestContext TestContext { get; set; } = null!;
 
+    [ClassInitialize]
+    public static void WarmModel(TestContext _) => AssemblyHooks.WarmModel(() => new PetContext(new Simulation()));
+
     private abstract class Pet
     {
         public int Id { get; set; }