net/http, internal/testenv: find go binary in PATH

Fixes #14901

Change-Id: Ia32e09767374a341c9a36c5d977d47d7d1a82315
Reviewed-on: https://go-review.googlesource.com/20967
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/src/internal/testenv/testenv.go b/src/internal/testenv/testenv.go
index 99b2a2ea15..6c007f185c 100644
--- a/src/internal/testenv/testenv.go
+++ b/src/internal/testenv/testenv.go
@@ -12,6 +12,7 @@ package testenv
 
 import (
 	"os"
+	"os/exec"
 	"runtime"
 	"strings"
 	"testing"
@@ -62,6 +63,22 @@ func MustHaveGoRun(t *testing.T) {
 	}
 }
 
+// GoToolPath reports the path to the Go tool.
+// If the tool is unavailable GoToolPath calls t.Skip.
+// If the tool should be available and isn't, GoToolPath calls t.Fatal.
+func GoToolPath(t *testing.T) string {
+	MustHaveGoBuild(t)
+	var exeSuffix string
+	if runtime.GOOS == "windows" {
+		exeSuffix = ".exe"
+	}
+	goBin, err := exec.LookPath("go" + exeSuffix)
+	if err != nil {
+		t.Fatal("cannot find go tool: %v", err)
+	}
+	return goBin
+}
+
 // HasExec reports whether the current system can start new processes
 // using os.StartProcess or (more commonly) exec.Command.
 func HasExec() bool {