all: consolidate cgo requirement checks

Many tools test check for the ability to compile cgo programs.
Consolidate them all into testenv.NeedsTool("cgo").

Change-Id: I62c96e7b4dc72df34b8fdbf10326c7d19e0613e8
Reviewed-on: https://go-review.googlesource.com/c/tools/+/234108
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

cmd/gorename/cgo_test.go

@@ -1,11 +0,0 @@
-// Copyright 2017 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.
-
-// +build cgo
-
-package main_test
-
-func init() {
-	haveCGO = true
-}

cmd/gorename/gorename_test.go

@@ -18,8 +18,6 @@ import (
 	"golang.org/x/tools/internal/testenv"
 )
 
-var haveCGO bool
-
 type test struct {
 	offset, from, to string // specify the arguments
 	fileSpecified    bool   // true if the offset or from args specify a specific file
@@ -31,10 +29,8 @@ type test struct {
 
 // Test that renaming that would modify cgo files will produce an error and not modify the file.
 func TestGeneratedFiles(t *testing.T) {
-	if !haveCGO {
-		t.Skipf("skipping test: no cgo")
-	}
 	testenv.NeedsTool(t, "go")
+	testenv.NeedsTool(t, "cgo")
 
 	tmp, bin, cleanup := buildGorename(t)
 	defer cleanup()

go/packages/packages115_test.go

@@ -12,6 +12,7 @@ import (
 
 	"golang.org/x/tools/go/packages"
 	"golang.org/x/tools/go/packages/packagestest"
+	"golang.org/x/tools/internal/testenv"
 )
 
 // TestInvalidFilesInXTest checks the fix for golang/go#37971.
@@ -48,11 +49,7 @@ func TestTypecheckCgo(t *testing.T) {
 }
 
 func testTypecheckCgo(t *testing.T, exporter packagestest.Exporter) {
-	// The android builders have a complex setup which causes this test to fail. See discussion on
-	// golang.org/cl/214943 for more details.
-	if !hasGoBuild() {
-		t.Skip("this test can't run on platforms without go build. See discussion on golang.org/cl/214943 for more details.")
-	}
+	testenv.NeedsTool(t, "cgo")
 
 	const cgo = `package cgo
 		import "C"

go/packages/packages_test.go

@@ -2768,25 +2768,3 @@ func copyAll(srcPath, dstPath string) error {
 		return nil
 	})
 }
-
-// Stolen from internal/testenv package in core.
-// 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 {
-	if os.Getenv("GO_GCFLAGS") != "" {
-		// It's too much work to require every caller of the go command
-		// to pass along "-gcflags="+os.Getenv("GO_GCFLAGS").
-		// For now, if $GO_GCFLAGS is set, report that we simply can't
-		// run go build.
-		return false
-	}
-	switch runtime.GOOS {
-	case "android", "js":
-		return false
-	case "darwin":
-		if strings.HasPrefix(runtime.GOARCH, "arm") {
-			return false
-		}
-	}
-	return true
-}

go/packages/packagescgo_test.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build cgo
-
 package packages_test
 
 import (
@@ -73,11 +71,7 @@ func TestCgoNoSyntax(t *testing.T) {
 	packagestest.TestAll(t, testCgoNoSyntax)
 }
 func testCgoNoSyntax(t *testing.T, exporter packagestest.Exporter) {
-	// The android builders have a complex setup which causes this test to fail. See discussion on
-	// golang.org/cl/214943 for more details.
-	if !hasGoBuild() {
-		t.Skip("this test can't run on platforms without go build. See discussion on golang.org/cl/214943 for more details.")
-	}
+	testenv.NeedsTool(t, "cgo")
 
 	exported := packagestest.Export(t, exporter, []packagestest.Module{{
 		Name: "golang.org/fake",
@@ -118,9 +112,7 @@ func TestCgoBadPkgConfig(t *testing.T) {
 	packagestest.TestAll(t, testCgoBadPkgConfig)
 }
 func testCgoBadPkgConfig(t *testing.T, exporter packagestest.Exporter) {
-	if !hasGoBuild() {
-		t.Skip("this test can't run on platforms without go build. See discussion on golang.org/cl/214943 for more details.")
-	}
+	testenv.NeedsTool(t, "cgo")
 
 	exported := packagestest.Export(t, exporter, []packagestest.Module{{
 		Name: "golang.org/fake",

internal/lsp/regtest/cgo_test.go

@@ -1,21 +1,18 @@
-//+build go1.15,cgo
+//+build go1.15
 
 package regtest
 
 import (
-	"runtime"
 	"testing"
 
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
+	"golang.org/x/tools/internal/testenv"
 )
 
 func TestRegenerateCgo(t *testing.T) {
-	// The android builders have a complex setup which causes this test to fail. See discussion on
-	// golang.org/cl/214943 for more details.
-	if runtime.GOOS == "android" {
-		t.Skip("android not supported")
-	}
+	testenv.NeedsTool(t, "cgo")
+
 	const workspace = `
 -- go.mod --
 module example.com

internal/lsp/tests/tests.go

@@ -16,7 +16,6 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
-	"runtime"
 	"sort"
 	"strconv"
 	"strings"
@@ -30,6 +29,7 @@ import (
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 	"golang.org/x/tools/internal/span"
+	"golang.org/x/tools/internal/testenv"
 	"golang.org/x/tools/txtar"
 )
 
@@ -231,8 +231,7 @@ func DefaultOptions() source.Options {
 }
 
 var (
-	haveCgo = false
-	go115   = false
+	go115 = false
 )
 
 // Load creates the folder structure required when testing with modules.
@@ -453,8 +452,8 @@ func Run(t *testing.T, tests Tests, data *Data) {
 			for i, e := range exp {
 				t.Run(SpanName(src)+"_"+strconv.Itoa(i), func(t *testing.T) {
 					t.Helper()
-					if (!haveCgo || runtime.GOOS == "android") && strings.Contains(t.Name(), "cgo") {
-						t.Skip("test requires cgo, not supported")
+					if strings.Contains(t.Name(), "cgo") {
+						testenv.NeedsTool(t, "cgo")
 					}
 					if !go115 && strings.Contains(t.Name(), "declarecgo") {
 						t.Skip("test requires Go 1.15")
@@ -614,8 +613,8 @@ func Run(t *testing.T, tests Tests, data *Data) {
 		for spn, d := range data.Definitions {
 			t.Run(SpanName(spn), func(t *testing.T) {
 				t.Helper()
-				if (!haveCgo || runtime.GOOS == "android") && strings.Contains(t.Name(), "cgo") {
-					t.Skip("test requires cgo, not supported")
+				if strings.Contains(t.Name(), "cgo") {
+					testenv.NeedsTool(t, "cgo")
 				}
 				if !go115 && strings.Contains(t.Name(), "declarecgo") {
 					t.Skip("test requires Go 1.15")

internal/lsp/tests/tests_cgo.go

@@ -1,7 +0,0 @@
-// +build cgo
-
-package tests
-
-func init() {
-	haveCgo = true
-}

internal/testenv/testenv.go

@@ -40,6 +40,18 @@ var checkGoGoroot struct {
 }
 
 func hasTool(tool string) error {
+	if tool == "cgo" {
+		out, err := exec.Command("go", "env", "CGO_ENABLED").CombinedOutput()
+		if err != nil {
+			return err
+		}
+		enabled := strings.TrimSpace(string(out))
+		if enabled != "1" {
+			return fmt.Errorf("cgo not enabled: CGO_ENABLED=%q", enabled)
+		}
+		return nil
+	}
+
 	_, err := exec.LookPath(tool)
 	if err != nil {
 		return err
@@ -125,6 +137,7 @@ func allowMissingTool(tool string) bool {
 }
 
 // NeedsTool skips t if the named tool is not present in the path.
+// As a special case, "cgo" means "go" is present and can compile cgo programs.
 func NeedsTool(t Testing, tool string) {
 	if t, ok := t.(helperer); ok {
 		t.Helper()