--- /dev/null
+// Copyright 2019 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 contains helper functions for skipping tests
+// based on which tools are present in the environment.
+package testenv
+
+import (
+ "fmt"
+ "io/ioutil"
+ "os"
+ "os/exec"
+ "runtime"
+ "strings"
+ "sync"
+)
+
+// Testing is an abstraction of a *testing.T.
+type Testing interface {
+ Skipf(format string, args ...interface{})
+ Fatalf(format string, args ...interface{})
+}
+
+type helperer interface {
+ Helper()
+}
+
+// packageMainIsDevel reports whether the module containing package main
+// is a development version (if module information is available).
+//
+// Builds in GOPATH mode and builds that lack module information are assumed to
+// be development versions.
+var packageMainIsDevel = func() bool { return true }
+
+var checkGoGoroot struct {
+ once sync.Once
+ err error
+}
+
+func hasTool(tool string) error {
+ _, err := exec.LookPath(tool)
+ if err != nil {
+ return err
+ }
+
+ switch tool {
+ case "patch":
+ // check that the patch tools supports the -o argument
+ temp, err := ioutil.TempFile("", "patch-test")
+ if err != nil {
+ return err
+ }
+ temp.Close()
+ defer os.Remove(temp.Name())
+ cmd := exec.Command(tool, "-o", temp.Name())
+ if err := cmd.Run(); err != nil {
+ return err
+ }
+
+ case "go":
+ checkGoGoroot.once.Do(func() {
+ // Ensure that the 'go' command found by exec.LookPath is from the correct
+ // GOROOT. Otherwise, 'some/path/go test ./...' will test against some
+ // version of the 'go' binary other than 'some/path/go', which is almost
+ // certainly not what the user intended.
+ out, err := exec.Command(tool, "env", "GOROOT").CombinedOutput()
+ if err != nil {
+ checkGoGoroot.err = err
+ return
+ }
+ GOROOT := strings.TrimSpace(string(out))
+ if GOROOT != runtime.GOROOT() {
+ checkGoGoroot.err = fmt.Errorf("'go env GOROOT' does not match runtime.GOROOT:\n\tgo env: %s\n\tGOROOT: %s", GOROOT, runtime.GOROOT())
+ }
+ })
+ if checkGoGoroot.err != nil {
+ return checkGoGoroot.err
+ }
+ }
+
+ return nil
+}
+
+func allowMissingTool(tool string) bool {
+ if runtime.GOOS == "android" {
+ // Android builds generally run tests on a separate machine from the build,
+ // so don't expect any external tools to be available.
+ return true
+ }
+
+ switch tool {
+ case "go":
+ if os.Getenv("GO_BUILDER_NAME") == "illumos-amd64-joyent" {
+ // Work around a misconfigured builder (see https://golang.org/issue/33950).
+ return true
+ }
+ case "diff":
+ if os.Getenv("GO_BUILDER_NAME") != "" {
+ return true
+ }
+ case "patch":
+ if os.Getenv("GO_BUILDER_NAME") != "" {
+ return true
+ }
+ }
+
+ // If a developer is actively working on this test, we expect them to have all
+ // of its dependencies installed. However, if it's just a dependency of some
+ // other module (for example, being run via 'go test all'), we should be more
+ // tolerant of unusual environments.
+ return !packageMainIsDevel()
+}
+
+// NeedsTool skips t if the named tool is not present in the path.
+func NeedsTool(t Testing, tool string) {
+ if t, ok := t.(helperer); ok {
+ t.Helper()
+ }
+ err := hasTool(tool)
+ if err == nil {
+ return
+ }
+ if allowMissingTool(tool) {
+ t.Skipf("skipping because %s tool not available: %v", tool, err)
+ } else {
+ t.Fatalf("%s tool not available: %v", tool, err)
+ }
+}
+
+// NeedsGoPackages skips t if the go/packages driver (or 'go' tool) implied by
+// the current process environment is not present in the path.
+func NeedsGoPackages(t Testing) {
+ if t, ok := t.(helperer); ok {
+ t.Helper()
+ }
+
+ tool := os.Getenv("GOPACKAGESDRIVER")
+ switch tool {
+ case "off":
+ // "off" forces go/packages to use the go command.
+ tool = "go"
+ case "":
+ if _, err := exec.LookPath("gopackagesdriver"); err == nil {
+ tool = "gopackagesdriver"
+ } else {
+ tool = "go"
+ }
+ }
+
+ NeedsTool(t, tool)
+}
+
+// NeedsGoPackagesEnv skips t if the go/packages driver (or 'go' tool) implied
+// by env is not present in the path.
+func NeedsGoPackagesEnv(t Testing, env []string) {
+ if t, ok := t.(helperer); ok {
+ t.Helper()
+ }
+
+ for _, v := range env {
+ if strings.HasPrefix(v, "GOPACKAGESDRIVER=") {
+ tool := strings.TrimPrefix(v, "GOPACKAGESDRIVER=")
+ if tool == "off" {
+ NeedsTool(t, "go")
+ } else {
+ NeedsTool(t, tool)
+ }
+ return
+ }
+ }
+
+ NeedsGoPackages(t)
+}
+
+// ExitIfSmallMachine emits a helpful diagnostic and calls os.Exit(0) if the
+// current machine is a builder known to have scarce resources.
+//
+// It should be called from within a TestMain function.
+func ExitIfSmallMachine() {
+ if os.Getenv("GO_BUILDER_NAME") == "linux-arm" {
+ fmt.Fprintln(os.Stderr, "skipping test: linux-arm builder lacks sufficient memory (https://golang.org/issue/32834)")
+ os.Exit(0)
+ }
+}