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
// 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 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