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fizzbuzz_properties_test.go
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fizzbuzz_properties_test.go
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package gofizbuzz_test
import (
"math"
"math/rand"
"reflect"
"strconv"
"strings"
"testing"
"testing/quick"
"github.com/screwyprof/gofizzbuzz"
)
func TestFizzBuzzProperties(t *testing.T) {
mul3Fizz := func(i int) bool {
result := gofizbuzz.FizzBuzz(i * 3)
t.Log(i*3, result)
return strings.HasPrefix(result, "Fizz")
}
mul5Buzz := func(i int) bool {
result := gofizbuzz.FizzBuzz(i * 5)
t.Log(i*5, result)
return strings.HasSuffix(result, "Buzz")
}
restAreNums := func(i int) bool {
result := gofizbuzz.FizzBuzz(i)
t.Log(i, result)
return result == strconv.Itoa(i)
}
t.Run("it should start with Fizz for all multiples of 3", func(t *testing.T) {
t.Parallel()
if err := quick.Check(mul3Fizz, genCfg(div3Generator)); err != nil {
t.Errorf("expected Fizz for number: %v", err)
}
})
t.Run("it should end with Buzz for all multiples of 5", func(t *testing.T) {
t.Parallel()
if err := quick.Check(mul5Buzz, genCfg(div5Generator)); err != nil {
t.Errorf("expected Buzz for number: %v", err)
}
})
t.Run("it should return number as string for all values non-divisible by 3 or 5", func(t *testing.T) {
t.Parallel()
if err := quick.Check(restAreNums, genCfg(non3or5DivGenerator)); err != nil {
t.Errorf("expected string number for number: %v", err)
}
})
}
func div3Generator(r *rand.Rand) int {
return r.Intn(math.MaxInt32 / 3)
}
func div5Generator(r *rand.Rand) int {
return r.Intn(math.MaxInt32 / 5)
}
func non3or5DivGenerator(r *rand.Rand) int {
var num int
for {
num = r.Intn(math.MaxInt32)
if !(num%3 == 0 || num%5 == 0) {
break
}
}
return num
}
func genCfg(numGen func(*rand.Rand) int) *quick.Config {
f := func(args []reflect.Value, r *rand.Rand) {
for i := range args {
num := numGen(r)
args[i] = reflect.ValueOf(num)
}
}
return &quick.Config{Values: f}
}