Unit tests.

builder/amazon/chroot/copy_files.go

@@ -6,7 +6,7 @@ import (
 )
 
 func copySingle(dest string, src string, copyCommand string) error {
-	cpCommand := fmt.Sprintf("sudo cp -fn %s %s", src, dest)
+	cpCommand := fmt.Sprintf("%s %s %s", copyCommand, src, dest)
 	localCmd := exec.Command("/bin/sh", "-c", cpCommand)
 	if err := localCmd.Run(); err != nil {
 		return err

builder/amazon/chroot/copy_files_test.go

@@ -0,0 +1,42 @@
+package chroot
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"testing"
+)
+
+func TestCopyFile(t *testing.T) {
+	first, err := ioutil.TempFile("", "copy_files_test")
+	if err != nil {
+		t.Fatalf("couldn't create temp file.")
+	}
+	defer os.Remove(first.Name())
+	newName := first.Name() + "-new"
+
+	payload := "copy_files_test.go payload"
+	if _, err = first.WriteString(payload); err != nil {
+		t.Fatalf("Couldn't write payload to first file.")
+	}
+
+	if err := copySingle(newName, first.Name(), "cp"); err != nil {
+		t.Fatalf("Couldn't copy file")
+	}
+	defer os.Remove(newName)
+
+	second, err := os.Open(newName)
+	if err != nil {
+		t.Fatalf("Couldn't open copied file.")
+	}
+	defer second.Close()
+
+	var copiedPayload = make([]byte, len(payload))
+	if _, err := second.Read(copiedPayload); err != nil {
+		t.Fatalf("Couldn't open copied file for reading.")
+	}
+
+	if string(copiedPayload) != payload {
+		t.Fatalf("payload not copied.")
+	}
+}