FunctionTest.cs

[Fact]
public async void Function_Should_Return_Product_By_Id()
{
    // Mock IProductRepository
    var expected = new Product
    {
        Id = 1,
        ProductName = "Chai",
        UnitPrice = 10
    };
    var mockRepo = new Mock<IProductRepository>();
    mockRepo.Setup(m => m.GetProduct(It.IsAny<int>())).ReturnsAsync(expected);

    // Invoke the lambda function and confirm correct value is returned
    var function = new Function(mockRepo.Object);
    var result = await function.FunctionHandler("1", new TestLambdaContext());
    Assert.Equal(expected, result);
}
}