FsCheck: Generate Arbitrary of a ArrayList with its elements as Arbitraries in C#

Question

I am using FsCheck in C#, I want to generate Arbitrary of an ArrayList to do PropertyBasedTesting by having 100's of ArrayList. I have this ArrayList with defined Arbitraries (they cannot be changed) for each element in it -

E.g. System.Collections.ArrayList a = new System.Collections.ArrayList(); a.Add(Gen.Choose(1, 55)); a.Add(Arb.Generate<int>()); a.Add(Arb.Generate<string>())

How do I get an Arbitrary of this ArrayList?

Answer 1

Based on the example linked by Mark Seemann I created a complete compiling example. It doesn't provide much extra compared to the link, but it won't risk being broken in the future.

using System.Collections;
using FsCheck;
using FsCheck.Xunit;
using Xunit;
public class ArrayListArbritary
{
    public static Arbitrary<ArrayList> ArrayList() =>
        (from e1 in Gen.Choose(1, 15)
         from e2 in Arb.Generate<int>()
         from e3 in Arb.Generate<string>()
         select CreateArrayList(e1, e2, e3))
        .ToArbitrary();

    private static ArrayList CreateArrayList(params object[] elements) => new ArrayList(elements);
}

public class Tests
{
    public Tests()
    {
        Arb.Register<ArrayListArbritary>();
    }

    [Property]
    public void TestWithArrayList(ArrayList arrayList)
    {
        Assert.Equal(3, arrayList.Count);
    }
}