Migration from 2 to 3

[lloydjatkinson]

I have a test suite currently using FsCheck 2.x with C#. I upgraded to 3.x, and I can't find a migration guide.

Here are some of the errors I have.

The name 'Prop' does not exist in the current context:

        [Property]
        public Property EveryCellCanBeReached() =>
            Prop.ForAll(
                Generators.Grid(),
                Generators.Algorithm(),
                (grid, type) =>
                {
                     //...
                });

Fortunately that one was an easy fix using FsCheck.Fluent; but the rest I do not understand how to fix. I was hoping someone might be able to provide some pointers.

---

No overload for method 'From' takes 0 arguments. Previously this was used to simply select an arbitrary enum value, but now appears to expect a Gen?

        public static Arbitrary<AlgorithmType> Algorithm() =>
            Arb.From<AlgorithmType>();

---

        // 'Arb' does not contain a definition for 'Default'
        public static Arbitrary<PositiveInt> PositiveIntGreaterThanOne => Arb.Default.PositiveInt().Filter(x => x.Get > 1);

        public static Gen<PositiveInt> GeneratePositiveIntGreaterThanOne => PositiveIntGreaterThanOne.Generator;

        // 'Arb' does not contain a definition for 'Generate'
        public static Gen<PositiveInt> GeneratePositiveIntGreaterThanOneLessThanTwenty =>
            from value in Arb.Generate<PositiveInt>()
            where value.Get > 1 && value.Get <= 20
            select value;

---

[Property]
public Property MazesAreGeneratedDeterministically() =>
    Prop.ForAll(
        // 'Arb' does not contain a definition for 'Default'
        Arb.Default.PositiveInt().Filter(x => x.Get > 1),
        Generators.Algorithm(),
        // 'Arb' does not contain a definition for 'Default'
        Arb.Default.Int32().Filter(x => x != 0),
        (size, type, seed) => // ...

[kurtschelfthout]

There's a bit more info in the release notes: https://github.com/fscheck/FsCheck/blob/master/FsCheck%20Release%20Notes.md#300-beta1---5-september-2021

In particular there is no longer a single static override-able map of type -> Arbitrary instances. The built-in default map is accessible via ArbMap.Default https://fscheck.github.io/FsCheck/reference/fscheck-fluent-arbmap.html#Default

Here is an example of how to get a generator for int: https://github.com/fscheck/FsCheck/blob/master/examples/FsCheck.CSharpExamples/Program.cs#L154

Probably surrounding code is useful as well to get an idea for how the API works now.