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Package quick

import "testing/quick"
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Package quick implements utility functions to help with black box testing.

func Check

func Check(f interface{}, config *Config) (err error)

Check looks for an input to f, any function that returns bool, such that f returns false. It calls f repeatedly, with arbitrary values for each argument. If f returns false on a given input, Check returns that input as a *CheckError. For example:

func TestOddMultipleOfThree(t *testing.T) {
	f := func(x int) bool {
		y := OddMultipleOfThree(x)
		return y%2 == 1 && y%3 == 0
	}
	if err := quick.Check(f, nil); err != nil {
		t.Error(err)
	}
}

func CheckEqual

func CheckEqual(f, g interface{}, config *Config) (err error)

CheckEqual looks for an input on which f and g return different results. It calls f and g repeatedly with arbitrary values for each argument. If f and g return different answers, CheckEqual returns a *CheckEqualError describing the input and the outputs.

func Value

func Value(t reflect.Type, rand *rand.Rand) (value reflect.Value, ok bool)

Value returns an arbitrary value of the given type. If the type implements the Generator interface, that will be used. Note: To create arbitrary values for structs, all the fields must be exported.

type CheckEqualError

type CheckEqualError struct {
        CheckError
        Out1 []interface{}
        Out2 []interface{}
}

A CheckEqualError is the result CheckEqual finding an error.

func (*CheckEqualError) Error

func (s *CheckEqualError) Error() string

type CheckError

type CheckError struct {
        Count int
        In    []interface{}
}

A CheckError is the result of Check finding an error.

func (*CheckError) Error

func (s *CheckError) Error() string

type Config

type Config struct {
        // MaxCount sets the maximum number of iterations. If zero,
        // MaxCountScale is used.
        MaxCount int
        // MaxCountScale is a non-negative scale factor applied to the default
        // maximum. If zero, the default is unchanged.
        MaxCountScale float64
        // If non-nil, rand is a source of random numbers. Otherwise a default
        // pseudo-random source will be used.
        Rand *rand.Rand
        // If non-nil, the Values function generates a slice of arbitrary
        // reflect.Values that are congruent with the arguments to the function
        // being tested. Otherwise, the top-level Values function is used
        // to generate them.
        Values func([]reflect.Value, *rand.Rand)
}

A Config structure contains options for running a test.

type Generator

type Generator interface {
        // Generate returns a random instance of the type on which it is a
        // method using the size as a size hint.
        Generate(rand *rand.Rand, size int) reflect.Value
}

A Generator can generate random values of its own type.

type SetupError

type SetupError string

A SetupError is the result of an error in the way that check is being used, independent of the functions being tested.

func (SetupError) Error

func (s SetupError) Error() string