func Check(f interface{}, config *Config) 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(f, g interface{}, config *Config) 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(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.
A CheckEqualError is the result CheckEqual finding an error.
type CheckEqualError struct { CheckError Out1 []interface{} Out2 []interface{} }
func (s *CheckEqualError) Error() string
A CheckError is the result of Check finding an error.
type CheckError struct { Count int In []interface{} }
func (s *CheckError) Error() string
A Config structure contains options for running a test.
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 // Rand specifies a source of random numbers. // If nil, a default pseudo-random source will be used. Rand *rand.Rand // Values specifies a function to generate a slice of // arbitrary reflect.Values that are congruent with the // arguments to the function being tested. // If nil, the top-level Value function is used to generate them. Values func([]reflect.Value, *rand.Rand) }
A Generator can generate random values of its own type.
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 SetupError is the result of an error in the way that check is being used, independent of the functions being tested.
type SetupError string
func (s SetupError) Error() string