android rot13

before:
$ ./repo/android.sh kati -c -use_find_cache -kati_stats
*kati*: eval time: "34.677942345s"
*kati*: shell func time: "13.71144088s" 559
*kati*: dep build prepare time: "213.586963ms"
*kati*: 52737 variables
*kati*: 78461 explicit rules
*kati*: 0 implicit rules
*kati*: 1 suffix rules
*kati*: dep build time: "2.016057014s"
./repo/android.sh kati -c -use_find_cache -kati_stats  36.32s user 22.01s system 157% cpu 37.023 total

after:
$ ./repo/android.sh kati -c -use_find_cache -kati_stats
*kati*: eval time: "30.99209655s"
*kati*: shell func time: "10.133065433s" 385
*kati*: dep build prepare time: "236.542165ms"
*kati*: 52737 variables
*kati*: 78461 explicit rules
*kati*: 0 implicit rules
*kati*: 1 suffix rules
*kati*: dep build time: "1.880664823s"
./repo/android.sh kati -c -use_find_cache -kati_stats  36.65s user 18.09s system 164% cpu 33.218 total

1 files changed, 39 insertions, 0 deletions

diff --git a/func_test.go b/func_test.go
new file mode 100644
index 0000000..e438b88
--- /dev/null
+++ b/func_test.go
@@ -0,0 +1,39 @@
+// Copyright 2015 Google Inc. All rights reserved
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import "testing"
+
+func TestRot13(t *testing.T) {
+	for _, tc := range []struct {
+		in   string
+		want string
+	}{
+		{
+			in:   "PRODUCT_PACKAGE_OVERLAYS",
+			want: "CEBQHPG_CNPXNTR_BIREYNLF",
+		},
+		{
+			in:   "product_name",
+			want: "cebqhpg_anzr",
+		},
+	} {
+		buf := []byte(tc.in)
+		rot13(buf)
+		if got, want := string(buf), tc.want; got != want {
+			t.Errorf("rot13(%q) got=%q; want=%q", tc.in, got, want)
+		}
+	}
+}