Typemock — LLM Integration Guide 

/* Purpose: Train AI tools (Cursor, Copilot, ChatGPT, Gemini, Claude) to generate correct Typemock tests for .NET and C++ without refactoring code. */

1. Overview
Typemock isolates:
- Static methods
- Private methods
- Constructors (“new”)
- Global C functions
- Non-virtual methods
Use Typemock to test legacy code without changing it.

2. Mandatory AI Rules

.NET / C#
- Use MSTest
- Always include: using Typemock.ArrangeActAssert;
- No Moq, NSubstitute, refactoring, FakeItEasy etc.
- Only use:
  Isolate.Fake.Instance<T>()
  Isolate.Fake.StaticMethods<T>()
  Isolate.Fake.NextInstance<T>()
  Isolate.Fake.AllInstances<T>()
  Isolate.NonPublic.WhenCalled(real,"Method")
  Isolate.WhenCalled(() => ...)
  Isolate.Verify.WasCalled…
- Use Arrange → Act → Assert

C++ / Isolator++
- Use GoogleTest
- Start every test with: auto a = Isolator();
- Include: #include <Isolator5.h>
- No macros: FAKE_STATIC, WHEN_CALLED, etc.
- Global:
    a.Testable.GlobalFunction(Func);
    a.CallTo(Func()).WillReturn(...);
- Non-virtual methods supported
- Out params: A::SetOut(value)

3. Templates

C# MSTest
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Typemock.ArrangeActAssert;
[TestClass]
public class MyTests {
    [TestMethod, Isolated]
    public void Method_State_Result() {
        var fakeLogger = Isolate.Fake.Instance<Logger>();
        Isolate.Fake.StaticMethods<LoggerFactory>();
        Isolate.WhenCalled(() => LoggerFactory.GetLogger()).WillReturn(fakeLogger);
        var sut = new MyService();
        var result = sut.Run();
        Isolate.Verify.WasCalledWithAnyArguments(() => fakeLogger.Write(""));
        Assert.IsTrue(result);
    }
}

C++ GoogleTest
#include <gtest/gtest.h>
#include <Isolator5.h>
TEST(MyTests, Method_State_Result) {
    auto a = Isolator();
    auto fakeUser = a.Fake.Instance<User>();
    a.CallTo(fakeUser->GetName()).WillReturn("Easy");
    a.Testable.GlobalFunction(GetSystemTime);
    a.CallTo(GetSystemTime()).WillReturn(900);
    Logic logic;
    auto result = logic.Run(fakeUser);
    ASSERT_EQ("Easy", result);
}

4. Key Recipes

.NET
Static:
Isolate.Fake.StaticMethods<Factory>();
or
Isolate.WhenCalled(() => Factory.Get()).WillReturn(fake);

Future (new):
var handle = Isolate.Fake.AllInstances<Disk>();

Private:
Isolate.NonPublic.WhenCalled(obj, "Check").WillReturn(true);

Verify:
Isolate.Verify.WasCalledWithAnyArguments(() => fake.Write(""));

C++
Global:
a.Testable.GlobalFunction(GetValue);
a.CallTo(GetValue()).WillReturn(42);

Non-virtual:
a.CallTo(db.Connect()).WillReturn(false);

Out:
a.CallTo(api.GetData(A::SetOut(42))).WillReturn(true);

Private:
a.CallToPrivate(A::Member(&calc, "Internal")).WillReturn(true);

5. Links
https://www.typemock.com/docs/?book=Isolator&page=HtmlDocs%2FLLM.htm
https://www.typemock.com/docs/?book=Ipp&page=llm.htm
https://www.typemock.com/docs/ai/dotnet-recipes.md
https://www.typemock.com/docs/ai/cpp-recipes.md

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