1 files changed, 63 insertions, 0 deletions
diff --git a/lib/btrfs/btrfstree/node_exp.go b/lib/btrfs/btrfstree/node_exp.go
new file mode 100644
index 0000000..5311ea0
--- /dev/null
+++ b/lib/btrfs/btrfstree/node_exp.go
@@ -0,0 +1,63 @@
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package btrfstree
+
+import (
+	"fmt"
+
+	"github.com/datawire/dlib/derror"
+
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
+	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
+)
+
+type NodeExpectations struct {
+	LAddr containers.Optional[btrfsvol.LogicalAddr]
+	// Things knowable from the parent.
+	Level      containers.Optional[uint8]
+	Generation containers.Optional[btrfsprim.Generation]
+	Owner      func(btrfsprim.ObjID, btrfsprim.Generation) error
+	MinItem    containers.Optional[btrfsprim.Key]
+	// Things knowable from the structure of the tree.
+	MaxItem containers.Optional[btrfsprim.Key]
+}
+
+func (exp NodeExpectations) Check(node *Node) error {
+	var errs derror.MultiError
+	if exp.LAddr.OK && node.Head.Addr != exp.LAddr.Val {
+		errs = append(errs, fmt.Errorf("read from laddr=%v but claims to be at laddr=%v",
+			exp.LAddr.Val, node.Head.Addr))
+	}
+	if exp.Level.OK && node.Head.Level != exp.Level.Val {
+		errs = append(errs, fmt.Errorf("expected level=%v but claims to be level=%v",
+			exp.Level.Val, node.Head.Level))
+	}
+	if exp.Generation.OK && node.Head.Generation != exp.Generation.Val {
+		errs = append(errs, fmt.Errorf("expected generation=%v but claims to be generation=%v",
+			exp.Generation.Val, node.Head.Generation))
+	}
+	if exp.Owner != nil {
+		if err := exp.Owner(node.Head.Owner, node.Head.Generation); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	if node.Head.NumItems == 0 {
+		errs = append(errs, fmt.Errorf("has no items"))
+	} else {
+		if minItem, _ := node.MinItem(); exp.MinItem.OK && exp.MinItem.Val.Compare(minItem) > 0 {
+			errs = append(errs, fmt.Errorf("expected minItem>=%v but node has minItem=%v",
+				exp.MinItem, minItem))
+		}
+		if maxItem, _ := node.MaxItem(); exp.MaxItem.OK && exp.MaxItem.Val.Compare(maxItem) < 0 {
+			errs = append(errs, fmt.Errorf("expected maxItem<=%v but node has maxItem=%v",
+				exp.MaxItem, maxItem))
+		}
+	}
+	if len(errs) > 0 {
+		return errs
+	}
+	return nil
+}