test(syncoid): Add test to verify out-of-order snapshot sync

This commit adds a regression test for the out-of-order snapshot
replication issue.

The new test case manipulates the system clock with `setdate` to create
snapshots with non-monotonic `creation` timestamps but a correct,
sequential `createtxg`. It then runs `syncoid` and verifies that all
snapshots were replicated, which is only possible if they are ordered
correctly by `createtxg`.

See #815 for the original test.

tests/syncoid/011_sync_out-of-order_snapshots/run.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+# test verifying snapshots with out-of-order snapshot creation datetimes
+
+set -x
+set -e
+
+. ../../common/lib.sh
+
+POOL_IMAGE="/tmp/jimsalterjrs_sanoid_815.img"
+POOL_SIZE="64M"
+POOL_NAME="jimsalterjrs_sanoid_815"
+
+truncate -s "${POOL_SIZE}" "${POOL_IMAGE}"
+
+zpool create -m none -f "${POOL_NAME}" "${POOL_IMAGE}"
+
+function cleanUp {
+  zpool export "${POOL_NAME}"
+  rm -f "${POOL_IMAGE}"
+}
+
+# export pool and remove the image in any case
+trap cleanUp EXIT
+
+zfs create "${POOL_NAME}"/before
+zfs snapshot "${POOL_NAME}"/before@this-snapshot-should-make-it-into-the-after-dataset
+
+disableTimeSync
+setdate 1155533696
+zfs snapshot "${POOL_NAME}"/before@oldest-snapshot
+
+zfs snapshot "${POOL_NAME}"/before@another-snapshot-does-not-matter
+../../../syncoid --sendoptions="Lec" "${POOL_NAME}"/before "${POOL_NAME}"/after
+
+# verify
+saveSnapshotList "${POOL_NAME}" "snapshot-list.txt"
+
+grep "${POOL_NAME}/before@this-snapshot-should-make-it-into-the-after-dataset" "snapshot-list.txt" || exit $?
+grep "${POOL_NAME}/after@this-snapshot-should-make-it-into-the-after-dataset" "snapshot-list.txt" || exit $?
+grep "${POOL_NAME}/before@oldest-snapshot" "snapshot-list.txt" || exit $?
+grep "${POOL_NAME}/after@oldest-snapshot" "snapshot-list.txt" || exit $?
+grep "${POOL_NAME}/before@another-snapshot-does-not-matter" "snapshot-list.txt" || exit $?
+grep "${POOL_NAME}/after@another-snapshot-does-not-matter" "snapshot-list.txt" || exit $?
+
+exit 0