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// Copyright 2017 The Bazel Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package starlark
import (
"flag"
"fmt"
"log"
"math"
"math/big"
"os"
"os/exec"
"runtime"
"strings"
"testing"
)
// TestIntOpts exercises integer arithmetic, especially at the boundaries.
func TestIntOpts(t *testing.T) {
f := MakeInt64
left, right := big.NewInt(math.MinInt32), big.NewInt(math.MaxInt32)
for i, test := range []struct {
val Int
want string
}{
// Add
{f(math.MaxInt32).Add(f(1)), "80000000"},
{f(math.MinInt32).Add(f(-1)), "-80000001"},
// Mul
{f(math.MaxInt32).Mul(f(math.MaxInt32)), "3fffffff00000001"},
{f(math.MinInt32).Mul(f(math.MinInt32)), "4000000000000000"},
{f(math.MaxUint32).Mul(f(math.MaxUint32)), "fffffffe00000001"},
{f(math.MinInt32).Mul(f(-1)), "80000000"},
// Div
{f(math.MinInt32).Div(f(-1)), "80000000"},
{f(1 << 31).Div(f(2)), "40000000"},
// And
{f(math.MaxInt32).And(f(math.MaxInt32)), "7fffffff"},
{f(math.MinInt32).And(f(math.MinInt32)), "-80000000"},
{f(1 << 33).And(f(1 << 32)), "0"},
// Mod
{f(1 << 32).Mod(f(2)), "0"},
// Or
{f(1 << 32).Or(f(0)), "100000000"},
{f(math.MaxInt32).Or(f(0)), "7fffffff"},
{f(math.MaxUint32).Or(f(0)), "ffffffff"},
{f(math.MinInt32).Or(f(math.MinInt32)), "-80000000"},
// Xor
{f(math.MinInt32).Xor(f(-1)), "7fffffff"},
// Not
{f(math.MinInt32).Not(), "7fffffff"},
{f(math.MaxInt32).Not(), "-80000000"},
// Shift
{f(1).Lsh(31), "80000000"},
{f(1).Lsh(32), "100000000"},
{f(math.MaxInt32 + 1).Rsh(1), "40000000"},
{f(math.MinInt32 * 2).Rsh(1), "-80000000"},
} {
if got := fmt.Sprintf("%x", test.val); got != test.want {
t.Errorf("%d equals %s, want %s", i, got, test.want)
}
small, big := test.val.get()
if small < math.MinInt32 || math.MaxInt32 < small {
t.Errorf("expected big, %d %s", i, test.val)
}
if big == nil {
continue
}
if small != 0 {
t.Errorf("expected 0 small, %d %s with %d", i, test.val, small)
}
if big.Cmp(left) >= 0 && big.Cmp(right) <= 0 {
t.Errorf("expected small, %d %s", i, test.val)
}
}
}
func TestImmutabilityMakeBigInt(t *testing.T) {
// use max int64 for the test
expect := int64(^uint64(0) >> 1)
mutint := big.NewInt(expect)
value := MakeBigInt(mutint)
mutint.Set(big.NewInt(1))
got, _ := value.Int64()
if got != expect {
t.Errorf("expected %d, got %d", expect, got)
}
}
func TestImmutabilityBigInt(t *testing.T) {
// use 1 and max int64 for the test
for _, expect := range []int64{1, int64(^uint64(0) >> 1)} {
value := MakeBigInt(big.NewInt(expect))
bigint := value.BigInt()
bigint.Set(big.NewInt(2))
got, _ := value.Int64()
if got != expect {
t.Errorf("expected %d, got %d", expect, got)
}
}
}
// TestIntFallback creates a small Int value in a child process with
// limited address space to ensure that it still works, but prints a warning.
func TestIntFallback(t *testing.T) {
if runtime.GOOS != "linux" {
t.Skipf("test disabled on this platform (requires ulimit -v)")
}
exe, err := os.Executable()
if err != nil {
t.Fatalf("can't find file name of executable: %v", err)
}
// ulimit -v limits the address space in KB. Not portable.
// 4GB is enough for the Go runtime but not for the optimization.
cmd := exec.Command("/bin/sh", "-c", fmt.Sprintf("ulimit -v 4000000 && %q --entry=intfallback", exe))
out, err := cmd.CombinedOutput()
if err != nil {
t.Fatalf("intfallback subcommand failed: %v\n%s", err, out)
}
// Check the warning was printed.
if !strings.Contains(string(out), "Integer performance may suffer") {
t.Errorf("expected warning was not printed. Output=<<%s>>", out)
}
}
// intfallback is called in a child process with limited address space.
func intfallback() {
const want = 123
if got, _ := MakeBigInt(big.NewInt(want)).Int64(); got != want {
log.Fatalf("intfallback: got %d, want %d", got, want)
}
}
// The --entry flag invokes an alternate entry point, for use in subprocess tests.
var testEntry = flag.String("entry", "", "child process entry-point")
func TestMain(m *testing.M) {
// In some build systems, notably Blaze, flag.Parse is called before TestMain,
// in violation of the TestMain contract, making this second call a no-op.
flag.Parse()
switch *testEntry {
case "":
os.Exit(m.Run()) // normal case
case "intfallback":
intfallback()
default:
log.Fatalf("unknown entry point: %s", *testEntry)
}
}
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