1 files changed, 47 insertions, 0 deletions
diff --git a/libgo/go/runtime/env_test.go b/libgo/go/runtime/env_test.go
new file mode 100644
index 00000000000..2399e46faa9
--- /dev/null
+++ b/libgo/go/runtime/env_test.go
@@ -0,0 +1,47 @@
+// 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 runtime_test
+
+import (
+	"runtime"
+	"syscall"
+	"testing"
+)
+
+func TestFixedGOROOT(t *testing.T) {
+	if runtime.GOOS == "plan9" {
+		t.Skipf("skipping plan9, it is inconsistent by allowing GOROOT to be updated by Setenv")
+	}
+
+	// Restore both the real GOROOT environment variable, and runtime's copies:
+	if orig, ok := syscall.Getenv("GOROOT"); ok {
+		defer syscall.Setenv("GOROOT", orig)
+	} else {
+		defer syscall.Unsetenv("GOROOT")
+	}
+	envs := runtime.Envs()
+	oldenvs := append([]string{}, envs...)
+	defer runtime.SetEnvs(oldenvs)
+
+	// attempt to reuse existing envs backing array.
+	want := runtime.GOROOT()
+	runtime.SetEnvs(append(envs[:0], "GOROOT="+want))
+
+	if got := runtime.GOROOT(); got != want {
+		t.Errorf(`initial runtime.GOROOT()=%q, want %q`, got, want)
+	}
+	if err := syscall.Setenv("GOROOT", "/os"); err != nil {
+		t.Fatal(err)
+	}
+	if got := runtime.GOROOT(); got != want {
+		t.Errorf(`after setenv runtime.GOROOT()=%q, want %q`, got, want)
+	}
+	if err := syscall.Unsetenv("GOROOT"); err != nil {
+		t.Fatal(err)
+	}
+	if got := runtime.GOROOT(); got != want {
+		t.Errorf(`after unsetenv runtime.GOROOT()=%q, want %q`, got, want)
+	}
+}