zfs: filesystem versioning and diffing

zfs/diff_test.go

@@ -0,0 +1,93 @@
+package zfs
+
+import (
+	"github.com/stretchr/testify/assert"
+	"strings"
+	"testing"
+)
+
+func fsvlist(fsv ...string) (r []FilesystemVersion) {
+
+	r = make([]FilesystemVersion, len(fsv))
+	for i, f := range fsv {
+		if strings.HasPrefix(f, "#") {
+			r[i] = FilesystemVersion{
+				Name: strings.TrimPrefix(f, "#"),
+				Type: Bookmark,
+			}
+		} else if strings.HasPrefix(f, "@") {
+			r[i] = FilesystemVersion{
+				Name: strings.TrimPrefix(f, "@"),
+				Type: Snapshot,
+			}
+		} else {
+			panic("invalid character")
+		}
+	}
+	return
+}
+
+func doTest(left, right []FilesystemVersion, validate func(d FilesystemDiff)) {
+	var d FilesystemDiff
+	d = MakeFilesystemDiff(left, right)
+	validate(d)
+}
+
+func TestMakeFilesystemDiff_IncrementalSnapshots(t *testing.T) {
+
+	l := fsvlist
+
+	// basic functionality
+	doTest(l("@a", "@b"), l("@a", "@b", "@c", "@d"), func(d FilesystemDiff) {
+		assert.Equal(t, l("@b", "@c", "@d"), d.IncrementalPath)
+	})
+
+	// no common ancestor
+	doTest(l(), l("@a"), func(d FilesystemDiff) {
+		assert.Nil(t, d.IncrementalPath)
+		assert.False(t, d.Diverged)
+		assert.Equal(t, l("@a"), d.MRCAPathRight)
+	})
+	doTest(l("@a", "@b"), l("@c", "@d"), func(d FilesystemDiff) {
+		assert.Nil(t, d.IncrementalPath)
+		assert.False(t, d.Diverged)
+		assert.Equal(t, l("@c", "@d"), d.MRCAPathRight)
+	})
+
+	// divergence is detected
+	doTest(l("@a", "@b1"), l("@a", "@b2"), func(d FilesystemDiff) {
+		assert.Nil(t, d.IncrementalPath)
+		assert.True(t, d.Diverged)
+		assert.Equal(t, l("@a", "@b1"), d.MRCAPathLeft)
+		assert.Equal(t, l("@a", "@b2"), d.MRCAPathRight)
+	})
+
+	// gaps before most recent common ancestor do not matter
+	doTest(l("@a", "@b", "@c"), l("@a", "@c", "@d"), func(d FilesystemDiff) {
+		assert.Equal(t, l("@c", "@d"), d.IncrementalPath)
+	})
+
+}
+
+func TestMakeFilesystemDiff_BookmarksSupport(t *testing.T) {
+	l := fsvlist
+
+	// bookmarks are used
+	doTest(l("@a"), l("#a", "@b"), func(d FilesystemDiff) {
+		assert.Equal(t, l("#a", "@b"), d.IncrementalPath)
+	})
+
+	// boomarks are stripped from IncrementalPath (cannot send incrementally)
+	doTest(l("@a"), l("#a", "#b", "@c"), func(d FilesystemDiff) {
+		assert.Equal(t, l("#a", "@c"), d.IncrementalPath)
+	})
+
+	// test that snapshots are preferred over bookmarks in IncrementalPath
+	doTest(l("@a"), l("#a", "@a", "@b"), func(d FilesystemDiff) {
+		assert.Equal(t, l("@a", "@b"), d.IncrementalPath)
+	})
+	doTest(l("@a"), l("@a", "#a", "@b"), func(d FilesystemDiff) {
+		assert.Equal(t, l("@a", "@b"), d.IncrementalPath)
+	})
+
+}