From 5561fe05a1ec79c9bca966376211b2ab81959671 Mon Sep 17 00:00:00 2001
From: Evan Phoenix <evan@phx.io>
Date: Wed, 20 Oct 2021 11:47:23 -0700
Subject: [PATCH] Handle applying to the whole doc. Fixes #142

---
 v5/patch.go      | 42 ++++++++++++++++++++++++++++++++++++++++++
 v5/patch_test.go | 31 +++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/v5/patch.go b/v5/patch.go
index ad04eef..117f2c0 100644
--- a/v5/patch.go
+++ b/v5/patch.go
@@ -845,6 +845,29 @@ func (p Patch) replace(doc *container, op Operation, options *ApplyOptions) erro
 		return errors.Wrapf(err, "replace operation failed to decode path")
 	}
 
+	if path == "" {
+		val := op.value()
+
+		if val.which == eRaw {
+			if !val.tryDoc() {
+				if !val.tryAry() {
+					return errors.Wrapf(err, "replace operation value must be object or array")
+				}
+			}
+		}
+
+		switch val.which {
+		case eAry:
+			*doc = &val.ary
+		case eDoc:
+			*doc = val.doc
+		case eRaw:
+			return errors.Wrapf(err, "replace operation hit impossible case")
+		}
+
+		return nil
+	}
+
 	con, key := findObject(doc, path, options)
 
 	if con == nil {
@@ -911,6 +934,25 @@ func (p Patch) test(doc *container, op Operation, options *ApplyOptions) error {
 		return errors.Wrapf(err, "test operation failed to decode path")
 	}
 
+	if path == "" {
+		var self lazyNode
+
+		switch sv := (*doc).(type) {
+		case *partialDoc:
+			self.doc = sv
+			self.which = eDoc
+		case *partialArray:
+			self.ary = *sv
+			self.which = eAry
+		}
+
+		if self.equal(op.value()) {
+			return nil
+		}
+
+		return errors.Wrapf(ErrTestFailed, "testing value %s failed", path)
+	}
+
 	con, key := findObject(doc, path, options)
 
 	if con == nil {
diff --git a/v5/patch_test.go b/v5/patch_test.go
index c3a30e5..3fa079e 100644
--- a/v5/patch_test.go
+++ b/v5/patch_test.go
@@ -540,6 +540,37 @@ var Cases = []Case{
 		false,
 		true,
 	},
+	{
+		`{
+	"id": "00000000-0000-0000-0000-000000000000",
+	"parentID": "00000000-0000-0000-0000-000000000000"
+}`,
+		`[
+  {
+    "op": "test",
+    "path": "",
+    "value": {
+      "id": "00000000-0000-0000-0000-000000000000",
+      "parentID": "00000000-0000-0000-0000-000000000000"
+    }
+  },
+  {
+    "op": "replace",
+    "path": "",
+    "value": {
+      "id": "759981e8-ec68-4639-a83e-513225914ecb",
+      "originalID": "bar",
+      "parentID": "00000000-0000-0000-0000-000000000000"
+    }
+  }
+]`,
+		`{
+  "id" : "759981e8-ec68-4639-a83e-513225914ecb",
+  "originalID" : "bar",
+  "parentID" : "00000000-0000-0000-0000-000000000000"
+}`,
+		false, true,
+	},
 }
 
 type BadCase struct {