"strings"
	"sync"
	"testing"
)

var flagCheck = flag.Bool("check", false, "run API checks")

func TestMain(m *testing.M) {
	flag.Parse()
	for _, c := range contexts {
		c.Compiler = build.Default.Compiler
	}
	build.Default.GOROOT = testenv.GOROOT(nil)

	os.Exit(m.Run())
}

var (
	updateGolden = flag.Bool("updategolden", false, "update golden files")
)

func TestGolden(t *testing.T) {
	if *flagCheck {

local version in preference to any other version.

The cgo tool is enabled by default for native builds on systems where
it is expected to work. It is disabled by default when cross-compiling
as well as when the CC environment variable is unset and the default
C compiler (typically gcc or clang) cannot be found on the system PATH.
You can override the default by setting the CGO_ENABLED

//go:build !compiler_bootstrap

package main

import (
	"go/ast"
	"go/token"
)

func (f *File) walkUnexpected(x interface{}, context astContext, visit func(*File, interface{}, astContext)) {
	switch n := x.(type) {
	default:
		error_(token.NoPos, "unexpected type %T in walk", x)
		panic("unexpected type")

	case *ast.IndexListExpr:
		f.walk(&n.X, ctxExpr, visit)
		f.walk(n.Indices, ctxExpr, visit)
	}
}

// license that can be found in the LICENSE file.

package main

import (
	"fmt"
	"os"
)

func main() {
	if len(os.Args) != 2 {
		fatal("usage: callback testname")
	}
	switch os.Args[1] {
	default:
		fatal("unknown test %q", os.Args[1])
	case "Call":
		testCall()
	case "Callback":
		testCallback()
	}
	println("OK")
}

func fatal(f string, args ...any) {

	// Tediously, RLIMIT_NPROC was left out of the syscall package,
	// probably because it is not in POSIX.1, so we define it here.
	// It is not defined on Solaris.
	var nproc int
	setNproc := true
	switch runtime.GOOS {
	default:
		setNproc = false
	case "aix":
		nproc = 9
	case "linux":
		nproc = 6
	case "darwin", "dragonfly", "freebsd", "netbsd", "openbsd":
		nproc = 7
	}
	if setNproc {
		var rlim syscall.Rlimit

a single one that can proceed is chosen via a uniform pseudo-random selection.
Otherwise, if there is a default case, that case is chosen.
If there is no default case, the "select" statement blocks until
at least one of the communications can proceed.
</li>

<li>
Unless the selected case is the default case, the respective communication
operation is executed.
</li>

<li>

pkg syscall (netbsd-386), const MAP_INHERIT_COPY = 1
pkg syscall (netbsd-386), const MAP_INHERIT_COPY ideal-int
pkg syscall (netbsd-386), const MAP_INHERIT_DEFAULT = 1
pkg syscall (netbsd-386), const MAP_INHERIT_DEFAULT ideal-int
pkg syscall (netbsd-386), const MAP_INHERIT_DONATE_COPY = 3
pkg syscall (netbsd-386), const MAP_INHERIT_DONATE_COPY ideal-int
pkg syscall (netbsd-386), const MAP_INHERIT_NONE = 2

pkg syscall (netbsd-arm64-cgo), const IP_ADD_MEMBERSHIP = 12
pkg syscall (netbsd-arm64-cgo), const IP_DEFAULT_MULTICAST_LOOP = 1
pkg syscall (netbsd-arm64-cgo), const IP_DEFAULT_MULTICAST_LOOP ideal-int
pkg syscall (netbsd-arm64-cgo), const IP_DEFAULT_MULTICAST_TTL = 1
pkg syscall (netbsd-arm64-cgo), const IP_DEFAULT_MULTICAST_TTL ideal-int
pkg syscall (netbsd-arm64-cgo), const IP_DF = 16384

	visit(f, x, context)
	switch n := x.(type) {
	case *ast.Expr:
		f.walk(*n, context, visit)

	// everything else just recurs
	default:
		f.walkUnexpected(x, context, visit)

	case nil:

	// These are ordered and grouped to match ../../go/ast/ast.go
	case *ast.Field:
		if len(n.Names) == 0 && context == ctxField {

			wantError := "bytes.Buffer: reader returned negative count from Read"
			if err.Error() != wantError {
				t.Fatalf("recovered panic: got %v, want %v", err.Error(), wantError)
			}
		default:
			t.Fatalf("unexpected panic value: %#v", err)
		}
	}()

	b.ReadFrom(new(negativeReader))
}

func TestWriteTo(t *testing.T) {
	var buf Buffer
	for i := 3; i < 30; i += 3 {