maybe fix sharding

Author: FGasper

internal/verifier/change_stream_test.go

@@ -249,6 +249,12 @@ func (suite *IntegrationTestSuite) TestEventBeforeWritesOff() {
 	checkDoneChan := make(chan struct{})
 	checkContinueChan := make(chan struct{})
 
+	db := suite.srcMongoClient.Database(suite.DBNameForTest())
+	coll := db.Collection("mycoll")
+	suite.Require().NoError(
+		db.CreateCollection(ctx, coll.Name()),
+	)
+
 	// start verifier
 	verifierDoneChan := make(chan struct{})
 	go func() {
@@ -261,9 +267,6 @@ func (suite *IntegrationTestSuite) TestEventBeforeWritesOff() {
 	// wait for generation 1
 	<-checkDoneChan
 
-	db := suite.srcMongoClient.Database(suite.DBNameForTest())
-	coll := db.Collection("mycoll")
-
 	docsCount := 10_000
 	docs := lo.RepeatBy(docsCount, func(_ int) bson.D { return bson.D{} })
 	_, err := coll.InsertMany(

internal/verifier/clustertime.go

@@ -28,8 +28,8 @@ func GetNewClusterTime(
 
 	var clusterTime primitive.Timestamp
 
-	// First we just fetch the latest cluster time without updating any
-	// shards’ oplogs.
+	// First we just fetch the latest cluster time among all shards without
+	// updating any shards’ oplogs.
 	err := retryer.RunForTransientErrorsOnly(
 		ctx,
 		logger,
@@ -107,7 +107,10 @@ func syncClusterTimeAcrossShards(
 	)
 
 	if err != nil {
-		return primitive.Timestamp{}, err
+		return primitive.Timestamp{}, errors.Wrap(
+			err,
+			"failed to append note to oplog",
+		)
 	}
 
 	return getOpTimeFromRawResponse(rawResponse)