math,os,os/*: use testenv.Executable

As some callers don't have a testing context, modify testenv.Executable
to accept nil (similar to how testenv.GOROOT works).

Change-Id: I39112a7869933785a26b5cb6520055b3cc42b847
Reviewed-on: https://go-review.googlesource.com/c/go/+/609835
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

1 files changed, 3 insertions, 8 deletions

diff --git a/src/os/exec/lp_windows_test.go b/src/os/exec/lp_windows_test.go
index a92a29799f..15b2a0032f 100644
--- a/src/os/exec/lp_windows_test.go
+++ b/src/os/exec/lp_windows_test.go
@@ -25,13 +25,8 @@ func init() {
 	registerHelperCommand("printpath", cmdPrintPath)
 }
 
-func cmdPrintPath(args ...string) {
-	exe, err := os.Executable()
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "Executable: %v\n", err)
-		os.Exit(1)
-	}
-	fmt.Println(exe)
+func cmdPrintPath(_ ...string) {
+	fmt.Println(testenv.Executable(nil))
 }
 
 // makePATH returns a PATH variable referring to the
@@ -82,7 +77,7 @@ func installProgs(t *testing.T, root string, files []string) {
 // (We use a copy instead of just a symlink to ensure that os.Executable
 // always reports an unambiguous path, regardless of how it is implemented.)
 func installExe(t *testing.T, dstPath string) {
-	src, err := os.Open(exePath(t))
+	src, err := os.Open(testenv.Executable(t))
 	if err != nil {
 		t.Fatal(err)
 	}