zfs: userrefs, platformtests for ListFilesystemVersions and ListMapping (likely needs fixup from next commit)

platformtest/tests/listFilesystems.go

@@ -0,0 +1,33 @@
+package tests
+
+import (
+	"strings"
+
+	"github.com/stretchr/testify/require"
+	"github.com/zrepl/zrepl/platformtest"
+	"github.com/zrepl/zrepl/zfs"
+)
+
+func ListFilesystemsNoFilter(t *platformtest.Context) {
+	platformtest.Run(t, platformtest.PanicErr, t.RootDataset, `
+		DESTROYROOT
+		CREATEROOT
+		R  zfs create -V 10M "${ROOTDS}/bar baz"
+		+  "foo bar"
+		+  "foo bar/bar blup"
+		+  "foo bar/blah"
+		R  zfs create -V 10M "${ROOTDS}/foo bar/blah/a volume"
+	`)
+
+	fss, err := zfs.ZFSListMapping(t, zfs.NoFilter())
+	require.NoError(t, err)
+	var onlyTestPool []*zfs.DatasetPath
+	for _, fs := range fss {
+		if strings.HasPrefix(fs.ToString(), t.RootDataset) {
+			onlyTestPool = append(onlyTestPool, fs)
+		}
+	}
+	onlyTestPoolStr := datasetToStringSortedTrimPrefix(mustDatasetPath(t.RootDataset), onlyTestPool)
+	require.Equal(t, []string{"bar baz", "foo bar", "foo bar/bar blup", "foo bar/blah", "foo bar/blah/a volume"}, onlyTestPoolStr)
+
+}