AnyUnit.Style.FsUnit 1.3.0

AnyUnit.Style.FsUnit

FsUnit-style F# assertions for AnyUnit - x |> should equal y-shaped assertions, on top of AnyUnit.Constraints' constraint model. Assertions only - pair this with AnyUnit.Style.Nunit, or the core's own AnyUnit.Style.Core, for [<Test>]/[<TestFixture>] discovery.

F#: open order matters

F# has no C# CS0104. When two opened namespaces export the same simple name the last open wins, silently - no error, no warning. Put the style's open where it will not be shadowed:

open AnyUnit                // exceptions, TestCapabilities, [<RequiresCapability>]
open AnyUnit.Constraints
open AnyUnit.Style.Nunit    // the attribute style - LAST

Opening two attribute styles at once (AnyUnit.Style.Nunit and AnyUnit.Style.Core, say, or .Nunit and .MsTest, which all export an AssertionHelper) is the case to avoid: whichever comes last provides [<Test>]/[<TestFixture>], and since each style's own TestAttribute.TestInvoke is what dispatches that style's [<SetUp>]/ [<TearDown>]/[<Ignore>], picking up the wrong one stops a fixture's setup and teardown running with nothing to say so. Before 1.3.0 this could happen by accident, because the core's built-in style shared the AnyUnit namespace with the exception types; it now lives in AnyUnit.Style.Core (#66). ComboTests.FSharp/OpenOrder.fs pins it.

Usage

A test fixture derives AssertionHelper (this package's own, not AnyUnit.Style.Nunit's - both ultimately derive the same core AnyUnit.Run.AssertionHelper, so its should/shouldFail still resolve correctly against whichever style's Assert the fixture ends up with) for the instance-scoped this.should/this.shouldFail:

type MyTests() =
    inherit AnyUnit.Style.FsUnit.AssertionHelper()

    [<Test>]
    member this.``adds two numbers``() =
        (2 + 2) |> this.should equal 4

    [<Test>]
    member this.``throws on bad input``() =
        this.shouldFail (fun () -> failwith "boom")

this.printf/this.printfn write to the test's captured Log the same way Console.printf would write to the console.

Free-function should/shouldFail (no this. receiver) work exactly as in real FsUnit, including from a module-level [<Fact>] let test with no this at all: they assert through the running test (AnyUnit.Run. AmbientTest, which the engine sets around every test body), so the counts are real and a test with no assertion still reports NoError. Before 1.2.1 they went through the global Assert.GlobalStyle and were [<Obsolete>] for it; they now only fall back to that outside a running test.