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rasky/abs_test.go

Created January 13, 2018 13:36
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  1. rasky created this gist Jan 13, 2018.
    97 changes: 97 additions & 0 deletions abs_test.go
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,97 @@
    package abs

    import (
    "math/rand"
    "reflect"
    "runtime"
    "strings"
    "testing"
    )

    const (
    MaxInt int64 = 1<<63 - 1
    MinInt int64 = -1 << 63
    )

    // An absFunc is a function that returns the absolute value of an integer.
    type absFunc func(int64) int64

    var (
    testInputs = []int64{MinInt + 1, MinInt + 2, -1, -0, 1, 2, MaxInt - 1, MaxInt}
    testOutputs = []int64{MaxInt, MaxInt - 1, 1, 0, 1, 2, MaxInt - 1, MaxInt}
    testFuncs = []absFunc{
    WithBranch,
    WithStdLib, // test failure expected on large numbers
    WithTwosComplement,
    WithASM,
    }
    )

    func funcName(v interface{}) string {
    s := runtime.FuncForPC(reflect.ValueOf(v).Pointer()).Name()
    return s[strings.LastIndex(s, ".")+1:]
    }

    // func TestAbs(t *testing.T) {
    // for _, f := range testFuncs {
    // testName := funcName(f)
    // t.Run(testName, func(t *testing.T) {
    // for i := 0; i < len(testInputs); i++ {
    // actual := f(testInputs[i])
    // if actual != testOutputs[i] {
    // t.Errorf("%s(%d)", testName, testInputs[i])
    // t.Errorf(" input: %064b (%d)", uint64(testInputs[i]), testInputs[i])
    // t.Errorf(" expected: %064b (%d)", uint64(testOutputs[i]), testOutputs[i])
    // t.Errorf(" actual: %064b (%d)", uint64(actual), actual)
    // }
    // }
    // })
    // }
    // }

    func randData(n int) []int64 {
    data := make([]int64, n)
    for i := range data {
    data[i] = rand.Int63() << 1
    }
    return data
    }

    func BenchmarkWithBranch(b *testing.B) {
    data := randData(1 << 16)
    b.ResetTimer()
    for n := 0; n < b.N; n++ {
    for _, x := range data {
    WithBranch(x)
    }
    }
    }
    func BenchmarkWithStdLib(b *testing.B) {
    data := randData(1 << 16)
    b.ResetTimer()
    for n := 0; n < b.N; n++ {
    for _, x := range data {
    WithStdLib(x)
    }
    }
    }

    func BenchmarkWithTwosComplement(b *testing.B) {
    data := randData(1 << 16)
    b.ResetTimer()
    for n := 0; n < b.N; n++ {
    for _, x := range data {
    WithTwosComplement(x)
    }
    }
    }

    func BenchmarkWithASM(b *testing.B) {
    data := randData(1 << 16)
    b.ResetTimer()
    for n := 0; n < b.N; n++ {
    for _, x := range data {
    WithASM(x)
    }
    }
    }