Gen

Namespace: FsCheck

Combinators to build custom random generators for any type.

Functions and values

Function or value	Description
`apply f gn` Signature: f:Gen<('a -> 'b)> -> gn:Gen<'a> -> Gen<'b> Type parameters: 'a, 'b	Apply the given Gen function to the given generator, aka the applicative <*> operator. CompiledName: `Apply`
`array2DOf g` Signature: g:Gen<'a> -> Gen<'a [,]> Type parameters: 'a	Generates a 2D array. The square root of the size is the maximum number of rows and columns. CompiledName: `Array2DOf`
`array2DOfDim (rows, cols) g` Signature: (rows:int * cols:int) -> g:Gen<'a> -> Gen<'a [,]> Type parameters: 'a	Generates a 2D array of the given dimensions. CompiledName: `Array2DOf`
`arrayOf g` Signature: g:Gen<'a> -> Gen<'a []> Type parameters: 'a	Generates an array using the specified generator. The maximum length is the size+1. CompiledName: `ArrayOf`
`arrayOfLength n g` Signature: n:int -> g:Gen<'a> -> Gen<'a []> Type parameters: 'a	Generates an array of a specified length. CompiledName: `ArrayOf`
`choose (l, h)` Signature: (l:int * h:int) -> Gen<int>	Generates an integer between l and h, inclusive. CompiledName: `Choose`
`constant v` Signature: v:'b -> Gen<'b> Type parameters: 'b	Always generate the same instance v. See also fresh. CompiledName: `Constant`
`elements xs` Signature: xs:seq<'a> -> Gen<'a> Type parameters: 'a	Build a generator that randomly generates one of the values in the given non-empty seq. CompiledName: `Elements`
`elementsArr values` Signature: values:'?211037 array -> Gen<'?211037> Type parameters: '?211037	Build a generator that randomly generates one of the values in the given non-empty seq. CompiledName: `Elements`
`eval size seed arg3` Signature: size:int -> seed:StdGen -> Gen<'b> -> 'b Type parameters: 'b	Generates a value of the give size with the given seed. CompiledName: `Eval`
`filter predicate generator` Signature: predicate:('a18 -> bool) -> generator:Gen<'a18> -> Gen<'a18> Type parameters: 'a18	Generates a value that satisfies a predicate. Contrary to tryFilter, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. The `filter` function is an alias for the `where` function. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `Filter`
`four g` Signature: g:Gen<'b> -> Gen<'b * 'b * 'b * 'b> Type parameters: 'b	Build a generator that generates a 4-tuple of the values generated by the given generator. CompiledName: `Four`
`frequency xs` Signature: xs:seq<int * Gen<'a18>> -> Gen<'a18> Type parameters: 'a18	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencySeqWeightAndValue (...)` Signature: weightedValues:seq<WeightAndValue<Gen<'a>>> -> Gen<'a> Type parameters: 'a	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencyTupleArr weightedValues` Signature: weightedValues:(int * Gen<'a>) [] -> Gen<'a> Type parameters: 'a	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencyWeightAndValueArr (...)` Signature: weightedValues:WeightAndValue<Gen<'a>> [] -> Gen<'a> Type parameters: 'a	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`fresh fv` Signature: fv:(unit -> '?211019) -> Gen<'?211019> Type parameters: '?211019	Generate a fresh instance every time the generator is called. Useful for mutable objects. See also constant. CompiledName: `Fresh`
`freshFunc fv` Signature: fv:Func<'?211021> -> Gen<'?211021> Type parameters: '?211021	Generate a fresh instance every time the generatoris called. Useful for mutable objects. See also constant. CompiledName: `Fresh`
`growingElements xs` Signature: xs:seq<'?211041> -> Gen<'?211041> Type parameters: '?211041	Build a generator that takes a non-empty sequence and randomly generates one of the values among an initial segment of that sequence. The size of this initial segment increases with the size parameter. Essentially this generator is Gen.elements but taking also the runtime size into account. CompiledName: `GrowingElements`
`listOf gn` Signature: gn:Gen<'a> -> Gen<'a list> Type parameters: 'a	Generates a list of random length. The maximum length depends on the size parameter. CompiledName: `ListOf`
`listOfLength n arb` Signature: n:int -> arb:Gen<'a18> -> Gen<'a18 list> Type parameters: 'a18	Generates a list of given length, containing values generated by the given generator. CompiledName: `ListOf`
`map f gen` Signature: f:('a -> 'b) -> gen:Gen<'a> -> Gen<'b> Type parameters: 'a, 'b	Apply the function f to the value in the generator, yielding a new generator. CompiledName: `Map`
`map2 f a b` Signature: f:('c -> 'd -> 'e) -> a:Gen<'c> -> b:Gen<'d> -> Gen<'e> Type parameters: 'c, 'd, 'e	Map the given function over values to a function over generators of those values. CompiledName: `Map2`
`map3 f a b c` Signature: f:('a18 -> 'a19 -> 'a20 -> 'a21) -> a:Gen<'a18> -> b:Gen<'a19> -> c:Gen<'a20> -> Gen<'a21> Type parameters: 'a18, 'a19, 'a20, 'a21	Map the given function over values to a function over generators of those values. CompiledName: `Map3`
`map4 f a b c d` Signature: f:('?211070 -> '?211071 -> '?211072 -> '?211073 -> '?211074) -> a:Gen<'?211070> -> b:Gen<'?211071> -> c:Gen<'?211072> -> d:Gen<'?211073> -> Gen<'?211074> Type parameters: '?211070, '?211071, '?211072, '?211073, '?211074	Map the given function over values to a function over generators of those values. CompiledName: `Map4`
`map5 f a b c d e` Signature: f:('a18 -> 'a19 -> 'a20 -> 'a21 -> 'a22 -> 'a23) -> a:Gen<'a18> -> b:Gen<'a19> -> c:Gen<'a20> -> d:Gen<'a21> -> e:Gen<'a22> -> Gen<'a23> Type parameters: 'a18, 'a19, 'a20, 'a21, 'a22, 'a23	Map the given function over values to a function over generators of those values. CompiledName: `Map5`
`map6 f a b c d e g` Signature: f:('?211085 -> '?211086 -> '?211087 -> '?211088 -> '?211089 -> '?211090 -> '?211091) -> a:Gen<'?211085> -> b:Gen<'?211086> -> c:Gen<'?211087> -> d:Gen<'?211088> -> e:Gen<'?211089> -> g:Gen<'?211090> -> Gen<'?211091> Type parameters: '?211085, '?211086, '?211087, '?211088, '?211089, '?211090, '?211091	Map the given function over values to a function over generators of those values. CompiledName: `Map6`
`nonEmptyListOf gn` Signature: gn:Gen<'b> -> Gen<'b list> Type parameters: 'b	Generates a non-empty list of random length. The maximum length depends on the size parameter. CompiledName: `NonEmptyListOf`
`oneof gens` Signature: gens:seq<Gen<'a>> -> Gen<'a> Type parameters: 'a	Build a generator that generates a value from one of the generators in the given non-empty seq, with equal probability. CompiledName: `OneOf`
`oneOfArr generators` Signature: generators:Gen<'?211045> array -> Gen<'?211045> Type parameters: '?211045	Build a generator that generates a value from one of the given generators, with equal probability. CompiledName: `OneOf`
`optionOf g` Signature: g:Gen<'b> -> Gen<'b option> Type parameters: 'b	Generate an option value that is 'None' 1/8 of the time.
`piles k sum` Signature: k:int -> sum:int -> Gen<int []>	Generates a random array of length k where the sum of all elements equals the given sum. CompiledName: `Piles`
`resize newSize arg2` Signature: newSize:int -> Gen<'b> -> Gen<'b> Type parameters: 'b	Override the current size of the test. resize n g invokes generator g with size parameter n. CompiledName: `Resize`
`sample size n generator` Signature: size:int -> n:int -> generator:Gen<'b> -> 'b list Type parameters: 'b	Generates n values of the given size. CompiledName: `Sample`
`sequence l` Signature: l:seq<Gen<'a>> -> Gen<'a list> Type parameters: 'a	Sequence the given enumerable of generators into a generator of a list. CompiledName: `SequenceToList`
`sequenceToArr generators` Signature: generators:Gen<'b> array -> Gen<'b []> Type parameters: 'b	Sequence the given array of generators into a generator of a array. CompiledName: `Sequence`
`sequenceToSeq generators` Signature: generators:seq<Gen<'?211109>> -> Gen<seq<'?211109>> Type parameters: '?211109	Sequence the given enumerable of generators into a generator of an enumerable. CompiledName: `Sequence`
`shuffle xs` Signature: xs:seq<'?211117> -> Gen<'?211117 array> Type parameters: '?211117	Generates a random permutation of the given sequence. CompiledName: `Shuffle`
`sized fgen` Signature: fgen:(int -> Gen<'b>) -> Gen<'b> Type parameters: 'b	Obtain the current size. sized g calls g, passing it the current size as a parameter. CompiledName: `Sized`
`sizedFunc sizedGen` Signature: sizedGen:Func<int,Gen<'?211028>> -> Gen<'?211028> Type parameters: '?211028	Obtain the current size. sized g calls g, passing it the current size as a parameter. CompiledName: `Sized`
`subListOf l` Signature: l:seq<'?211136> -> Gen<'?211136 list> Type parameters: '?211136	Generates sublists of the given sequence. CompiledName: `SubListOfToList`
`subListOfArr s` Signature: s:'?211140 array -> Gen<IList<'?211140>> Type parameters: '?211140	Generates sublists of the given arguments. CompiledName: `SubListOf`
`subListOfToIList s` Signature: s:seq<'?211138> -> Gen<IList<'?211138>> Type parameters: '?211138	Generates sublists of the given IEnumerable. CompiledName: `SubListOf`
`suchThat` Signature: ('?211129 -> bool) -> Gen<'?211129> -> Gen<'?211129> Type parameters: '?211129	Generates a value that satisfies a predicate. Contrary to suchThatOption, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. CompiledName: `SuchThat`
`suchThatOption` Signature: ('?211123 -> bool) -> Gen<'?211123> -> Gen<'?211123 option> Type parameters: '?211123	Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. CompiledName: `SuchThatOption`
`three g` Signature: g:Gen<'b> -> Gen<'b * 'b * 'b> Type parameters: 'b	Build a generator that generates a 3-tuple of the values generated by the given generator. CompiledName: `Three`
`tryFilter predicate generator` Signature: predicate:('?211121 -> bool) -> generator:Gen<'?211121> -> Gen<'?211121 option> Type parameters: '?211121	Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. The `tryFilter` function is an alias for the `tryWhere` function. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `TryFilter`
`tryWhere predicate generator` Signature: predicate:('a -> bool) -> generator:Gen<'a> -> Gen<'a option> Type parameters: 'a	Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. The `tryWhere` function is also aliased as `tryFilter`. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `TryWhere`
`two g` Signature: g:Gen<'a18> -> Gen<'a18 * 'a18> Type parameters: 'a18	Build a generator that generates a 2-tuple of the values generated by the given generator. CompiledName: `Two`
`unzip g` Signature: g:Gen<'?211100 * '?211101> -> Gen<'?211100> * Gen<'?211101> Type parameters: '?211100, '?211101	Split a generator of pairs into a pair of generators.
`unzip3 g` Signature: g:Gen<'?211103 * '?211104 * '?211105> -> Gen<'?211103> * Gen<'?211104> * Gen<'?211105> Type parameters: '?211103, '?211104, '?211105	Split a generator of 3-tuples into a 3-tuple of generators.
`where predicate generator` Signature: predicate:('b -> bool) -> generator:Gen<'b> -> Gen<'b> Type parameters: 'b	Generates a value that satisfies a predicate. Contrary to tryWhere, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. The `where` function is also aliased as `filter`. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `Where`
`zip f g` Signature: f:Gen<'?211093> -> g:Gen<'?211094> -> Gen<'?211093 * '?211094> Type parameters: '?211093, '?211094	Combine two generators into a generator of pairs.
`zip3 f g h` Signature: f:Gen<'?211096> -> g:Gen<'?211097> -> h:Gen<'?211098> -> Gen<'?211096 * '?211097 * '?211098> Type parameters: '?211096, '?211097, '?211098	Combine three generators into a generator of 3-tuples.