R3/tests/R3.Tests/FactoryTests/DeferTest.cs

namespace R3.Tests.FactoryTests;

public class DeferTest
{
    [Fact]
    public void Test()
    {
        var called = false;
        var def = Observable.Defer(() =>
        {
            called = true;
            return Observable.Range(1, 10);
        });

        called.Should().BeFalse();

        var list = def.ToLiveList();

        called.Should().BeTrue();
        
        list.AssertEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
    }
}