fscheck

问题 I have just started working with FsCheck and have been writing some simple tests. However I keep coming across an issue which causes Xunit to throw an exception which then kills the VS2012 test runner (tests appear to run forever). It seems as though any attempt to return a non-literal result causes this exception. Some examples: ///This will work, the test will trivially succeed and the result values ///will be available in the "test output" screen in VS2012's test explorer. let [<Property>]

问题 I need to write a simple method that receives a parameter (e.g. a string ) and does smth. Usually I'd end up with two tests. The first one would be a guard clause. The second would validate the expected behavior (for simplicity, the method shouldn't fail): [Fact] public void DoSmth_WithNull_Throws() { var sut = new Sut(); Assert.Throws<ArgumentNullException>(() => sut.DoSmth(null)); } [Fact] public void DoSmth_WithValidString_DoesNotThrow() { var s = "123"; var sut = new Sut(); sut.DoSmth(s);

问题 How do I implement multiple argument generation using FsCheck? I implemented the following to support multiple argument generation: // Setup let pieces = Arb.generate<Piece> |> Gen.filter (isKing >> not) |> Arb.fromGen let positionsList = Arb.generate<Space list> |> Arb.fromGen I then used these arguments to test the behavior of a function that's responsible for generating move options for a given checker: // Test Prop.forAll pieces <| fun piece -> Prop.forAll positionsList <| fun

问题 I try to write a FsCheck generator that generates strings with length in a given interval. My attempt is the following: let genString minLength maxLength = let isValidLength (s : string) = s.Length >= minLength && s.Length <= maxLength Arb.generate |> Gen.suchThat isValidLength |> Arb.fromGen ...and I get the error: "System.Exception : No instances of class FsCheck.Arbitrary`1[a] for type System.String with arguments set []" What am I doing wrong? thanks! UPDATE 1: I managed to write the

问题 I'm new on F#, and can't see how extract the int value from: let autoInc = FsCheck.Gen.choose(1,999) The compiler say the type is Gen<int> , but can't get the int from it!. I need to convert it to decimal, and both types are not compatible. 回答1: From a consumer's point of view, you can use the Gen.sample combinator which, given a generator (e.g. Gen.choose ), gives you back some example values. The signature of Gen.sample is: val sample : size:int -> n:int -> gn:Gen<'a> -> 'a list (* `size`

问题 I need generate unique non- null strings to be used as Dictionary keys. I tried something like: public static Gen<NonNull<string>> UniqueStrings() { return from s in Arb.Default.NonNull<string>().Generator select s; } Then I use UniqueString() in: public static Arb<Foo> Foos() { // Foo's constructor will use the string parameter // as key to an internal Dictionary return (from nonNullString in UniqueStrings() select new Foo(nonNullString.Item)).ToArbitrary(); } However, I get an exception in

问题 This question is a follow-up to an earlier question on using FsCheck to generate records. The original question was answered with a well composed example solution. However, prior to the answer being shared, I attempted to create a generator which is included below. Unfortunately, the generated records of type QueryRequest = {Symbol: string; StartDate: DateTime; EndDate: DateTime} have the following issues: Missing symbol Start dates earlier than January 1, 2000 End dates later than January 1,

问题 I'd like to use FsCheck (with XUnit) to create records of type: type QueryRequest = {Symbol: string; StartDate: DateTime; EndDate: DateTime} where Symbol is limited to 3 options - ORCL , IBM , AAPL , and StartDate and EndDate are limited to the range between January 1, 2000 and January 1, 2019 . However, I'm unclear as to how proceed. Should I use Arb.generate<T> or Arb.Default or some other utility upon which to base the generation and shrinking of the test cases? Update 1 Follow-on question

问题 As an exercise I wanted to implement a 2-3 finger tree. That should be the perfect opportunity to try out FsCheck's model-based testing. I decided to try the newer experimental version. So far I only coded one command for the test machine because I already fail at making that work—one the other hand it keeps the post short. The full code is available on GitHub. open CmdQ open Fuchu open FsCheck open FsCheck.Experimental type TestType = uint16 type ModelType = ResizeArray<TestType> type

问题 FsCheck allows a custom Arbitrary in its NUnit integration: [<Property(Verbose = true, Arbitrary= [typeof<Test.Arithmetic.MyArb>])>] static member MultiplyIdentity (x: int64) = x * 1 = x This syntax doesn't work. I feel a bit embarrassed to ask, but apparently I never needed this before: how do you specify the type in F# as an attribute parameter? Microsoft says nothing about it, nor does the Wikibooks project and I have some trouble googling this (the word type is omnipresent). Note 1: the