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

common/errors/transient_test.go

Index: common/errors/transient_test.go
diff --git a/common/errors/transient_test.go b/common/errors/transient_test.go
deleted file mode 100644
index 0829c72a4e0365effe0f24c4ab978dd9db170b1c..0000000000000000000000000000000000000000
--- a/common/errors/transient_test.go
+++ /dev/null
@@ -1,49 +0,0 @@
-// 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 errors
-
-import (
-	"errors"
-	"testing"
-
-	. "github.com/smartystreets/goconvey/convey"
-)
-
-func TestTransientError(t *testing.T) {
-	t.Parallel()
-
-	Convey(`A nil error`, t, func() {
-		err := error(nil)
-
-		Convey(`Is not transient.`, func() {
-			So(IsTransient(err), ShouldBeFalse)
-		})
-
-		Convey(`Returns nil when wrapped with a transient error.`, func() {
-			So(WrapTransient(err), ShouldBeNil)
-		})
-	})
-
-	Convey(`An error`, t, func() {
-		err := errors.New("test error")
-
-		Convey(`Is not transient.`, func() {
-			So(IsTransient(err), ShouldBeFalse)
-		})
-		Convey(`When wrapped with a transient error`, func() {
-			terr := WrapTransient(err)
-			Convey(`Has the same error string.`, func() {
-				So(terr.Error(), ShouldEqual, "test error")
-			})
-			Convey(`Is transient.`, func() {
-				So(IsTransient(terr), ShouldBeTrue)
-			})
-		})
-
-		Convey(`A MultiError with a transient sub-error is transient.`, func() {
-			So(IsTransient(MultiError{nil, WrapTransient(err), err}), ShouldBeTrue)
-		})
-	})
-}