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package gopter_test
import (
"errors"
"math"
"strconv"
"strings"
"github.com/leanovate/gopter"
"github.com/leanovate/gopter/gen"
"github.com/leanovate/gopter/prop"
)
// Fizzbuzz: See https://wikipedia.org/wiki/Fizz_buzz
func fizzbuzz(number int) (string, error) {
if number <= 0 {
return "", errors.New("Undefined")
}
switch {
case number%15 == 0:
return "FizzBuzz", nil
case number%3 == 0:
return "Fizz", nil
case number%5 == 0:
return "Buzz", nil
}
return strconv.Itoa(number), nil
}
func Example_fizzbuzz() {
properties := gopter.NewProperties(nil)
properties.Property("Undefined for all <= 0", prop.ForAll(
func(number int) bool {
result, err := fizzbuzz(number)
return err != nil && result == ""
},
gen.IntRange(math.MinInt32, 0),
))
properties.Property("Start with Fizz for all multiples of 3", prop.ForAll(
func(i int) bool {
result, err := fizzbuzz(i * 3)
return err == nil && strings.HasPrefix(result, "Fizz")
},
gen.IntRange(1, math.MaxInt32/3),
))
properties.Property("End with Buzz for all multiples of 5", prop.ForAll(
func(i int) bool {
result, err := fizzbuzz(i * 5)
return err == nil && strings.HasSuffix(result, "Buzz")
},
gen.IntRange(1, math.MaxInt32/5),
))
properties.Property("Int as string for all non-divisible by 3 or 5", prop.ForAll(
func(number int) bool {
result, err := fizzbuzz(number)
if err != nil {
return false
}
parsed, err := strconv.ParseInt(result, 10, 64)
return err == nil && parsed == int64(number)
},
gen.IntRange(1, math.MaxInt32).SuchThat(func(v interface{}) bool {
return v.(int)%3 != 0 && v.(int)%5 != 0
}),
))
// When using testing.T you might just use: properties.TestingRun(t)
properties.Run(gopter.ConsoleReporter(false))
// Output:
// + Undefined for all <= 0: OK, passed 100 tests.
// + Start with Fizz for all multiples of 3: OK, passed 100 tests.
// + End with Buzz for all multiples of 5: OK, passed 100 tests.
// + Int as string for all non-divisible by 3 or 5: OK, passed 100 tests.
}
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