FSharp

As awaiting doesn't work quite the same in F#, the syntax instead looks like this:

do! check Assert.That(...).IsSomething()

So a test could look like:

member this.CheckPositive() = async {
    let result = 1 + 1
    do! check (Assert.That(result).IsPositive())
}

F# is a lot more strict with type resolution when it comes to extension methods and method overloads. Because of that you may need to annotate the type for the assertions.

For example,

[<Test>]
[<Category("Pass")>]
member _.Test3() = async {
    let value = "1"
    do! check (Assert.That<string>(value).IsEqualTo("1"))
}

[<Test>]
[<Category("Fail")>]
member _.Throws1() = async {
    do! check (Assert.That<string>(fun () -> task { return new string([||]) }).ThrowsException())
}

[<Test>]
[<Category("Pass")>]
member _.Throws4() = async {
    do! check (Assert.That<bool>(fun () -> Task.FromResult(true)).ThrowsNothing())
}

taskAssert expression

For Task-based tests you can also use the taskAssert computation expression to avoid wrapping every assertion in check.

To use it, open the namespace:

open TUnit.Assertions.FSharp.TaskAssert

Inside a taskAssert block you can directly do! the assertion:

[<Test>]
[<Category("Pass")>]
member _.Test3() = taskAssert {
    let value = "1"
    do! Assert.That(value).IsEqualTo("1")
}