os: fix ForkExec() handling of envv == nil

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/1913047

1 files changed, 23 insertions, 0 deletions

diff --git a/src/pkg/exec/exec_test.go b/src/pkg/exec/exec_test.go
index 3e4ab7d780..898f42582b 100644
--- a/src/pkg/exec/exec_test.go
+++ b/src/pkg/exec/exec_test.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"io/ioutil"
 	"testing"
+	"os"
 )
 
 func TestRunCat(t *testing.T) {
@@ -84,3 +85,25 @@ func TestMergeWithStdout(t *testing.T) {
 		t.Fatal("close:", err)
 	}
 }
+
+func TestAddEnvVar(t *testing.T) {
+	err := os.Setenv("NEWVAR", "hello world")
+	if err != nil {
+		t.Fatal("setenv:", err)
+	}
+	cmd, err := Run("/bin/sh", []string{"sh", "-c", "echo $NEWVAR"}, nil, "",
+		DevNull, Pipe, DevNull)
+	if err != nil {
+		t.Fatal("run:", err)
+	}
+	buf, err := ioutil.ReadAll(cmd.Stdout)
+	if err != nil {
+		t.Fatal("read:", err)
+	}
+	if string(buf) != "hello world\n" {
+		t.Fatalf("read: got %q", buf)
+	}
+	if err = cmd.Close(); err != nil {
+		t.Fatal("close:", err)
+	}
+}