Add tests for WithPrefix option

Author: snorwin

handler.go

@@ -3,49 +3,49 @@ package jsonpatch
 // Handler is the interfaces used by the walker to create patches
 type Handler interface {
 	// Add creates a JSONPatch with an 'add' operation and appends it to the patch list
-	Add(path JSONPointer, modified interface{}) []JSONPatch
+	Add(pointer JSONPointer, modified interface{}) []JSONPatch
 
 	// Remove creates a JSONPatch with an 'remove' operation and appends it to the patch list
-	Remove(path JSONPointer, current interface{}) []JSONPatch
+	Remove(pointer JSONPointer, current interface{}) []JSONPatch
 
 	// Replace creates a JSONPatch with an 'replace' operation and appends it to the patch list
-	Replace(path JSONPointer, modified, current interface{}) []JSONPatch
+	Replace(pointer JSONPointer, modified, current interface{}) []JSONPatch
 }
 
 // DefaultHandler implements the Handler
 type DefaultHandler struct{}
 
 // Add implements Handler
-func (h *DefaultHandler) Add(path JSONPointer, value interface{}) []JSONPatch {
+func (h *DefaultHandler) Add(pointer JSONPointer, value interface{}) []JSONPatch {
 	// The 'add' operation either inserts a value into the array at the specified index or adds a new member to the object
 	// NOTE: If the target location specifies an object member that does exist, that member's value is replaced
 	return []JSONPatch{
 		{
 			Operation: "add",
-			Path:      path.String(),
+			Path:      pointer.String(),
 			Value:     value,
 		},
 	}
 }
 
 // Remove implements Handler
-func (h *DefaultHandler) Remove(path JSONPointer, _ interface{}) []JSONPatch {
-	// The 'remove' operation removes the value at the target location (specified by the path)
+func (h *DefaultHandler) Remove(pointer JSONPointer, _ interface{}) []JSONPatch {
+	// The 'remove' operation removes the value at the target location (specified by the pointer)
 	return []JSONPatch{
 		{
 			Operation: "remove",
-			Path:      path.String(),
+			Path:      pointer.String(),
 		},
 	}
 }
 
 // Replace implements Handler
-func (h *DefaultHandler) Replace(path JSONPointer, value, _ interface{}) []JSONPatch {
+func (h *DefaultHandler) Replace(pointer JSONPointer, value, _ interface{}) []JSONPatch {
 	// The 'replace' operation replaces the value at the target location with a new value
 	return []JSONPatch{
 		{
 			Operation: "replace",
-			Path:      path.String(),
+			Path:      pointer.String(),
 			Value:     value,
 		},
 	}

patch_test.go

@@ -320,6 +320,53 @@ var _ = Describe("JSONPatch", func() {
 			testPatchWithExpected(F{}, F{B: &B{Str: "don't remove me"}}, F{B: &B{Str: "don't remove me"}}, jsonpatch.WithPredicate(predicate))
 		})
 	})
+	Context("CreateJsonPatch_with_prefix", func() {
+		It("empty prefix", func() {
+			testPatchWithExpected(F{B: &B{Bool: true, Str: "str"}}, F{}, F{B: &B{Bool: true, Str: "str"}}, jsonpatch.WithPrefix([]string{""}))
+		})
+		It("pointer prefix", func() {
+			modified := F{A: &A{B: &B{Bool: true, Str: "str"}}}
+			current := F{A: &A{}}
+			expected := F{A: &A{B: &B{Bool: true, Str: "str"}}}
+
+			currentJSON, err := json.Marshal(current)
+			Ω(err).ShouldNot(HaveOccurred())
+			_, err = json.Marshal(modified)
+			Ω(err).ShouldNot(HaveOccurred())
+			expectedJSON, err := json.Marshal(expected)
+			Ω(err).ShouldNot(HaveOccurred())
+
+			bytes, _, err := jsonpatch.CreateJSONPatch(modified.A.B, current.A.B, jsonpatch.WithPrefix(jsonpatch.ParseJSONPointer("/a/ptr")))
+			Ω(err).ShouldNot(HaveOccurred())
+			Ω(bytes.String()).ShouldNot(Equal(""))
+			jsonPatch, err := jsonpatch2.DecodePatch(bytes)
+			Ω(err).ShouldNot(HaveOccurred())
+			patchedJSON, err := jsonPatch.Apply(currentJSON)
+			Ω(err).ShouldNot(HaveOccurred())
+			Ω(patchedJSON).Should(MatchJSON(expectedJSON))
+		})
+		It("string prefix", func() {
+			modified := F{B: &B{Bool: true, Str: "str"}}
+			current := F{}
+			expected := F{B: &B{Bool: true, Str: "str"}}
+
+			currentJSON, err := json.Marshal(current)
+			Ω(err).ShouldNot(HaveOccurred())
+			_, err = json.Marshal(modified)
+			Ω(err).ShouldNot(HaveOccurred())
+			expectedJSON, err := json.Marshal(expected)
+			Ω(err).ShouldNot(HaveOccurred())
+
+			bytes, _, err := jsonpatch.CreateJSONPatch(modified.B, current.B, jsonpatch.WithPrefix([]string{"b"}))
+			Ω(err).ShouldNot(HaveOccurred())
+			Ω(bytes.String()).ShouldNot(Equal(""))
+			jsonPatch, err := jsonpatch2.DecodePatch(bytes)
+			Ω(err).ShouldNot(HaveOccurred())
+			patchedJSON, err := jsonPatch.Apply(currentJSON)
+			Ω(err).ShouldNot(HaveOccurred())
+			Ω(patchedJSON).Should(MatchJSON(expectedJSON))
+		})
+	})
 	Context("CreateJsonPatch_errors", func() {
 		It("not matching types", func() {
 			_, _, err := jsonpatch.CreateJSONPatch(A{}, B{})