Move multierror logic into luci-go.

common/errors/errors_test.go

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package errors
-
-import (
-        "fmt"
-        "testing"
-
-        . "github.com/smartystreets/goconvey/convey"
-)
-
-func TestMark(t *testing.T) {
-        Convey("MakeMarkFn works", t, func() {
-                f := MakeMarkFn("errorsTest")
-
-                type Cat struct{ name string }
-
-                // unfortunately... the line numbers for these tests matter
-                c := &Cat{"dude"}
-                var err error
-                err = f(c)
-
-                So(err.Error(), ShouldEqual, "errorsTest - errors_test.go:23 - &{name:dude}")
-                So(f("hello").Error(), ShouldEqual, "errorsTest - errors_test.go:26 - hello")
-
-                So(err.(*MarkedError).Orig, ShouldEqual, c)
-
-                So(f(nil), ShouldBeNil)
-        })
-}
-
-func TestMultiError(t *testing.T) {
-        Convey("MultiError works", t, func() {
-                var me error = MultiError{fmt.Errorf("hello"), fmt.Errorf("bob")}
-
-                So(me.Error(), ShouldEqual, `["hello" "bob"]`)
-
-                Convey("MultiErrorFromErrors with errors works", func() {
-                        mec := make(chan error, 5)
-                        mec <- fmt.Errorf("what")
-                        mec <- nil
-                        mec <- MakeMarkFn("multiErr")("one-off")
-                        close(mec)
-
-                        err := MultiErrorFromErrors(mec)
-                        So(err.Error(), ShouldEqual, `["what" "multiErr - errors_test.go:44 - one-off"]`)
-                })
-
-                Convey("MultiErrorFromErrors with nil works", func() {
-                        So(MultiErrorFromErrors(nil), ShouldBeNil)
-
-                        c := make(chan error)
-                        close(c)
-                        So(MultiErrorFromErrors(c), ShouldBeNil)
-
-                        c = make(chan error, 4)
-                        c <- nil
-                        c <- nil
-                        close(c)
-                        So(MultiErrorFromErrors(c), ShouldBeNil)
-                })
-        })
-}
-
-func ExampleMakeMarkFn() {
-        // usually this would be in some global area of your library
-        mark := MakeMarkFn("cool_package")
-
-        data := 100 // Data can be anything!
-        err := mark(data)
-        fmt.Printf("got: %q\n", err)
-
-        marked := err.(*MarkedError)
-        fmt.Printf("original: %d", marked.Orig)
-
-        // Output:
-        // got: "cool_package - errors_test.go:72 - 100"
-        // original: 100
-}
-
-func ExampleMultiError() {
-        errCh := make(chan error, 10)
-        errCh <- nil // nils are ignored
-        errCh <- fmt.Errorf("what")
-        close(errCh)
-
-        err := MultiErrorFromErrors(errCh)
-        fmt.Printf("got: %s len=%d\n", err, len(err.(MultiError)))
-
-        errCh = make(chan error, 10)
-        errCh <- nil // and if the channel only has nils
-        close(errCh)
-
-        err = MultiErrorFromErrors(errCh) // then it returns nil
-        fmt.Printf("got: %v\n", err)
-
-        // Output:
-        // got: ["what"] len=1
-        // got: <nil>
-}