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package arbitrary_test
import (
"errors"
"math/cmplx"
"github.com/leanovate/gopter"
"github.com/leanovate/gopter/arbitrary"
"github.com/leanovate/gopter/gen"
)
type QudraticEquation struct {
A, B, C complex128
}
func (q *QudraticEquation) Eval(x complex128) complex128 {
return q.A*x*x + q.B*x + q.C
}
func (q *QudraticEquation) Solve() (complex128, complex128, error) {
if q.A == 0 {
return 0, 0, errors.New("No solution")
}
v := q.B*q.B - 4*q.A*q.C
v = cmplx.Sqrt(v)
return (-q.B + v) / 2 / q.A, (-q.B - v) / 2 / q.A, nil
}
func Example_quadratic() {
parameters := gopter.DefaultTestParametersWithSeed(1234) // Example should generate reproducible results, otherwise DefaultTestParameters() will suffice
arbitraries := arbitrary.DefaultArbitraries()
arbitraries.RegisterGen(gen.Complex128Box(-1e8-1e8i, 1e8+1e8i)) // Only use complex values within a range
properties := gopter.NewProperties(parameters)
properties.Property("Quadratic equations can be solved (as pointer)", arbitraries.ForAll(
func(quadratic *QudraticEquation) bool {
x1, x2, err := quadratic.Solve()
if err != nil {
return true
}
return cmplx.Abs(quadratic.Eval(x1)) < 1e-5 && cmplx.Abs(quadratic.Eval(x2)) < 1e-5
}))
properties.Property("Quadratic equations can be solved (as struct)", arbitraries.ForAll(
func(quadratic QudraticEquation) bool {
x1, x2, err := quadratic.Solve()
if err != nil {
return true
}
return cmplx.Abs(quadratic.Eval(x1)) < 1e-5 && cmplx.Abs(quadratic.Eval(x2)) < 1e-5
}))
properties.Property("Quadratic equations can be solved alternative", arbitraries.ForAll(
func(a, b, c complex128) bool {
quadratic := &QudraticEquation{
A: a,
B: b,
C: c,
}
x1, x2, err := quadratic.Solve()
if err != nil {
return true
}
return cmplx.Abs(quadratic.Eval(x1)) < 1e-5 && cmplx.Abs(quadratic.Eval(x2)) < 1e-5
}))
// When using testing.T you might just use: properties.TestingRun(t)
properties.Run(gopter.ConsoleReporter(false))
// Output:
// + Quadratic equations can be solved (as pointer): OK, passed 100 tests.
// + Quadratic equations can be solved (as struct): OK, passed 100 tests.
// + Quadratic equations can be solved alternative: OK, passed 100 tests.
}
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