go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/cv/internal/gerrit/mirror_test.go (about)

     1  // Copyright 2021 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gerrit
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  	"sort"
    21  	"testing"
    22  
    23  	"google.golang.org/grpc"
    24  
    25  	"go.chromium.org/luci/common/errors"
    26  
    27  	. "github.com/smartystreets/goconvey/convey"
    28  
    29  	. "go.chromium.org/luci/common/testing/assertions"
    30  )
    31  
    32  func TestMirrorIterator(t *testing.T) {
    33  	t.Parallel()
    34  
    35  	Convey("MirrorIterator and its factory work", t, func() {
    36  		ctx := context.Background()
    37  		const baseHost = "a.example.com"
    38  		Convey("No mirrors", func() {
    39  			it := newMirrorIterator(ctx)
    40  			So(it.Empty(), ShouldBeFalse)
    41  			So(it.next()(baseHost), ShouldResemble, baseHost)
    42  			So(it.Empty(), ShouldBeTrue)
    43  			So(it.next()(baseHost), ShouldResemble, baseHost)
    44  			So(it.Empty(), ShouldBeTrue)
    45  			So(it.next()(baseHost), ShouldResemble, baseHost)
    46  		})
    47  		Convey("One mirrors", func() {
    48  			it := newMirrorIterator(ctx, "m1-")
    49  			So(it.Empty(), ShouldBeFalse)
    50  			So(it.next()(baseHost), ShouldResemble, baseHost)
    51  			So(it.Empty(), ShouldBeFalse)
    52  			So(it.next()(baseHost), ShouldResemble, "m1-"+baseHost)
    53  			So(it.Empty(), ShouldBeTrue)
    54  			So(it.next()(baseHost), ShouldResemble, baseHost)
    55  		})
    56  		Convey("Shuffles mirrors", func() {
    57  			prefixes := make([]string, 10)
    58  			expectedHosts := make([]string, len(prefixes)+1)
    59  			expectedHosts[0] = baseHost
    60  			for i := range prefixes {
    61  				// use "m" prefix such that its lexicographically after baseHost itself.
    62  				p := fmt.Sprintf("m%d-", i)
    63  				prefixes[i] = p
    64  				expectedHosts[i+1] = p + baseHost
    65  			}
    66  			iterate := func() []string {
    67  				var actual []string
    68  				it := newMirrorIterator(ctx, prefixes...)
    69  				for !it.Empty() {
    70  					actual = append(actual, it.next()(baseHost))
    71  				}
    72  				return actual
    73  			}
    74  			act1 := iterate()
    75  			So(act1, ShouldNotResemble, expectedHosts)
    76  			act2 := iterate()
    77  			So(act2, ShouldNotResemble, expectedHosts)
    78  			So(act1, ShouldNotResemble, act2)
    79  
    80  			sort.Strings(act1)
    81  			So(act1, ShouldResemble, expectedHosts)
    82  			sort.Strings(act2)
    83  			So(act2, ShouldResemble, expectedHosts)
    84  		})
    85  		Convey("RetryIfStale works", func() {
    86  			it := &MirrorIterator{"", "m1", "m2"}
    87  
    88  			Convey("stops when mirrors are exhausted", func() {
    89  				tried := 0
    90  				err := it.RetryIfStale(func(grpc.CallOption) error {
    91  					tried += 1
    92  					return ErrStaleData
    93  				})
    94  				So(err, ShouldEqual, ErrStaleData)
    95  				So(tried, ShouldEqual, 3)
    96  			})
    97  
    98  			Convey("respects returned value, unwrapping if needed", func() {
    99  				tried := 0
   100  				err := it.RetryIfStale(func(grpc.CallOption) error {
   101  					tried += 1
   102  					if tried == 1 {
   103  						return errors.Annotate(ErrStaleData, "try #%d", tried).Err()
   104  					}
   105  					return errors.New("something else")
   106  				})
   107  				So(err, ShouldErrLike, "something else")
   108  				So(tried, ShouldEqual, 2)
   109  				So((*it)[0], ShouldResemble, "m2")
   110  			})
   111  
   112  			Convey("calls at least once even if empty", func() {
   113  				it.Next()
   114  				it.Next()
   115  				it.Next()
   116  				So(it.Empty(), ShouldBeTrue)
   117  				called := false
   118  				err := it.RetryIfStale(func(grpc.CallOption) error {
   119  					called = true
   120  					return nil
   121  				})
   122  				So(err, ShouldBeNil)
   123  				So(called, ShouldBeTrue)
   124  			})
   125  		})
   126  	})
   127  }