// Copyright 2015 The Go 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 testenv provides information about what functionality
// is available in different testing environments run by the Go team.
//
// It is an internal package because these details are specific
// to the Go team's test setup (on build.golang.org) and not
// fundamental to tests in general.
package testenv

import (
	"os"
	"runtime"
	"strings"
	"testing"
)

// Builder reports the name of the builder running this test
// (for example, "linux-amd64" or "windows-386-gce").
// If the test is not running on the build infrastructure,
// Builder returns the empty string.
func Builder() string {
	return os.Getenv("GO_BUILDER_NAME")
}

// HasGoBuild reports whether the current system can build programs with ``go build''
// and then run them with os.StartProcess or exec.Command.
func HasGoBuild() bool {
	switch runtime.GOOS {
	case "android", "nacl":
		return false
	case "darwin":
		if strings.HasPrefix(runtime.GOARCH, "arm") {
			return false
		}
	}
	return true
}

// MustHaveGoBuild checks that the current system can build programs with ``go build''
// and then run them with os.StartProcess or exec.Command.
// If not, MustHaveGoBuild calls t.Skip with an explanation.
func MustHaveGoBuild(t *testing.T) {
	if !HasGoBuild() {
		t.Skipf("skipping test: 'go build' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}

// HasGoRun reports whether the current system can run programs with ``go run.''
func HasGoRun() bool {
	// For now, having go run and having go build are the same.
	return HasGoBuild()
}

// MustHaveGoRun checks that the current system can run programs with ``go run.''
// If not, MustHaveGoRun calls t.Skip with an explanation.
func MustHaveGoRun(t *testing.T) {
	if !HasGoRun() {
		t.Skipf("skipping test: 'go run' not available on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}

// HasExec reports whether the current system can start new processes
// using os.StartProcess or (more commonly) exec.Command.
func HasExec() bool {
	switch runtime.GOOS {
	case "nacl":
		return false
	case "darwin":
		if strings.HasPrefix(runtime.GOARCH, "arm") {
			return false
		}
	}
	return true
}

// MustHaveExec checks that the current system can start new processes
// using os.StartProcess or (more commonly) exec.Command.
// If not, MustHaveExec calls t.Skip with an explanation.
func MustHaveExec(t *testing.T) {
	if !HasExec() {
		t.Skipf("skipping test: cannot exec subprocess on %s/%s", runtime.GOOS, runtime.GOARCH)
	}
}

// HasExternalNetwork reports whether the current system can use
// external (non-localhost) networks.
func HasExternalNetwork() bool {
	return !testing.Short()
}

// MustHaveExternalNetwork checks that the current system can use
// external (non-localhost) networks.
// If not, MustHaveExternalNetwork calls t.Skip with an explanation.
func MustHaveExternalNetwork(t *testing.T) {
	if testing.Short() {
		t.Skipf("skipping test: no external network in -short mode")
	}
}