auth: Make luci-go services trust signatures produced by the token server.

server/auth/internal/testing.go

+// Copyright 2015 The LUCI Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package internal
+
+import (
+        "bytes"
+        "io/ioutil"
+        "net/http"
+        "sync"
+
+        "golang.org/x/net/context"
+)
+
+var testTransportKey = "testTransport"
+
+// TestTransportCallback is used from unit tests.
+type TestTransportCallback func(r *http.Request, body string) (code int, response string)
+
+// WithTestTransport puts a testing transport in the context to use for fetches.
+func WithTestTransport(c context.Context, cb TestTransportCallback) context.Context {
+        return context.WithValue(c, &testTransportKey, &testTransport{cb: cb})
+}
+
+type testTransport struct {
+        lock sync.Mutex
+        cb   TestTransportCallback
+}
+
+func (t *testTransport) RoundTrip(r *http.Request) (*http.Response, error) {
+        t.lock.Lock()
+        defer t.lock.Unlock()
+        body, err := ioutil.ReadAll(r.Body)
+        r.Body.Close()
+        if err != nil {
+                return nil, err
+        }
+        code, resp := t.cb(r, string(body))
+        return &http.Response{
+                StatusCode: code,
+                Body:       ioutil.NopCloser(bytes.NewReader([]byte(resp))),
+        }, nil
+}