[errors] de-specialize Transient in favor of Tags.

common/auth/internal/luci_ctx_test.go

 // Copyright 2017 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 (
         "context"
         "encoding/json"
         "net"
         "net/http"
         "net/http/httptest"
         "testing"
         "time"
 
         "golang.org/x/oauth2"
 
         "github.com/luci/luci-go/common/auth/localauth/rpcs"
-        "github.com/luci/luci-go/common/errors"
+        "github.com/luci/luci-go/common/retry"
         "github.com/luci/luci-go/lucictx"
 
         . "github.com/luci/luci-go/common/testing/assertions"
         . "github.com/smartystreets/goconvey/convey"
 )
 
 func TestLUCIContextProvider(t *testing.T) {
         t.Parallel()
 
         Convey("Requires local_auth", t, func() {
@@ skipping 71 matching lines @@
                                 Secret:    []byte("zekret"),
                                 AccountID: "acc_id",
                         })
                 })
 
                 Convey("HTTP 500", func() {
                         responses <- 500
                         tok, err := p.MintToken(ctx, nil)
                         So(tok, ShouldBeNil)
                         So(err, ShouldErrLike, `local auth - HTTP 500`)
-                        So(errors.IsTransient(err), ShouldBeTrue)
+                        So(retry.Tag.In(err), ShouldBeTrue)
                 })
 
                 Convey("HTTP 403", func() {
                         responses <- 403
                         tok, err := p.MintToken(ctx, nil)
                         So(tok, ShouldBeNil)
                         So(err, ShouldErrLike, `local auth - HTTP 403`)
-                        So(errors.IsTransient(err), ShouldBeFalse)
+                        So(retry.Tag.In(err), ShouldBeFalse)
                 })
 
                 Convey("RPC level error", func() {
                         responses <- rpcs.GetOAuthTokenResponse{
                                 BaseResponse: rpcs.BaseResponse{
                                         ErrorCode:    123,
                                         ErrorMessage: "omg, error",
                                 },
                         }
                         tok, err := p.MintToken(ctx, nil)
                         So(tok, ShouldBeNil)
                         So(err, ShouldErrLike, `local auth - RPC code 123: omg, error`)
-                        So(errors.IsTransient(err), ShouldBeFalse)
+                        So(retry.Tag.In(err), ShouldBeFalse)
                 })
         })
 }