Support NUnit 5 on .NET 8

[Copilot]

FsUnit’s NUnit dependency and .NET 6 targets prevented consumers from upgrading to NUnit 5. This updates the repository to .NET 8 and adapts FsUnit to NUnit 5’s delegate APIs.

• NUnit compatibility: Upgrade to NUnit 5 and replace removed NUnit-specific delegates with System.Action.

  let shouldFail (f: unit -> unit) =
      System.Action(f) |> should throw typeof<AssertionException>

• Framework and packaging: Move project targets and package assets to .NET 8, which remains consumable by .NET 10 projects. Update documentation references and CI SDK setup; retain .NET 6 for the existing FAKE runner.

• Fixes Support NUnit 5 #309

[Copilot]

🟢 Approval recommended

The framework, packaging, CI, documentation, and NUnit delegate changes are consistent and covered by the existing test suites.

0 open findings

What changed in this PR

Updates FsUnit for NUnit 5 and .NET 8 while retaining .NET 6 for the FAKE runner.

Changes:

• Migrates projects, CI, documentation, and package assets to .NET 8.
• Upgrades NUnit to 5.0 and replaces removed delegates with System.Action.
• Regenerates Paket dependency constraints.

File	Description
.github/​workflows/​main.yml	Installs .NET 8 and FAKE’s .NET 6 SDK.
global.json	Pins the .NET 8 SDK.
paket.dependencies	Targets .NET 8 and requests NUnit 5.
paket.lock	Locks updated frameworks and dependencies.
docs/​NUnit.fsx	References .NET 8 assemblies.
docs/​index.fsx	References .NET 8 assemblies.
docs/​FsUnitTyped.fsx	References .NET 8 assemblies.
src/​FsUnit.NUnit/​FsUnit.fs	Adapts assertions to NUnit 5 delegates.
src/​FsUnit.NUnit/​FsUnitTyped.fs	Uses System.Action for typed assertions.
src/​FsUnit.NUnit/​FsUnit.NUnit.fsproj	Targets .NET 8.
src/​FsUnit.NUnit/​paket.template	Packages .NET 8 assets.
src/​FsUnit.Xunit/​FsUnit.Xunit.fsproj	Replaces its .NET 6 target.
src/​FsUnit.Xunit/​paket.template	Packages .NET 8 assets.
src/​FsUnit.MsTestUnit/​FsUnit.MsTest.fsproj	Replaces its .NET 6 target.
src/​FsUnit.MsTestUnit/​paket.template	Packages .NET 8 assets.
tests/​FsUnit.NUnit.Test/​FsUnit.NUnit.Test.fsproj	Runs NUnit tests on .NET 8.
tests/​FsUnit.Xunit.Test/​FsUnit.Xunit.Test.fsproj	Runs xUnit tests on .NET 8.
tests/​FsUnit.MsTest.Test/​FsUnit.MsTest.Test.fsproj	Runs MSTest tests on .NET 8.

🧠 Review effort: Balanced

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[CaptnCodr]

Besides that the dedicated project to substitute the FAKE script would be nice to drop .NET6 at some time.

[sergey-tihon]

How do you see it? Migration to Fun.Build or another solution?

[CaptnCodr]

Either that or run FAKE from a fsproj as the statement says:
fsprojects/FAKE#2875
And that is mentioned in the Getting started guide: https://fake.build/guide/getting-started.html#Run-FAKE-using-a-dedicated-build-project

[Wotee]

@CaptnCodr Like I said on the #309 I am willing to help to make these changes happen. I have a POC of that Fake build project on my local machine already and I can open a PR for that if you want. Or I can create another issue with detailed instructions if the Copilot way is the way you want to move forward.

[CaptnCodr]

@sergey-tihon Then we can merge this and @Wotee can open a PR for the Fake build project.

[sergey-tihon]

@Wotee, sorry, my bad. I've got an email about the new issue and assigned it to Copilot without checking PRs.
Please open a PR with the migration to the FAKE project