Address review feedback from #1896 (#1913)

## Description

- Adds accessor methods for size/modified
- Do not initialize folder in test with a modified time

## Does this PR need a docs update or release note?

- [x] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [ ] ⛔ No 

## Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [x] 🐹 Trivial/Minor

## Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Folder entries in backup details now include size and modified time for the hierarchy (#1896)
+
 ### Changed
 
 - **Breaking Change**:

src/pkg/backup/details/details.go

@@ -145,26 +145,9 @@ func (b *Builder) AddFoldersForItem(folders []FolderEntry, itemInfo ItemInfo) {
 		}
 
 		// Update the folder's size and modified time
-		var (
-			itemSize     int64
-			itemModified time.Time
-		)
+		itemModified := itemInfo.modified()
 
-		switch {
-		case itemInfo.Exchange != nil:
-			itemSize = itemInfo.Exchange.Size
-			itemModified = itemInfo.Exchange.Modified
-
-		case itemInfo.OneDrive != nil:
-			itemSize = itemInfo.OneDrive.Size
-			itemModified = itemInfo.OneDrive.Modified
-
-		case itemInfo.SharePoint != nil:
-			itemSize = itemInfo.SharePoint.Size
-			itemModified = itemInfo.SharePoint.Modified
-		}
-
-		folder.Info.Folder.Size += itemSize
+		folder.Info.Folder.Size += itemInfo.size()
 
 		if folder.Info.Folder.Modified.Before(itemModified) {
 			folder.Info.Folder.Modified = itemModified
@@ -346,6 +329,42 @@ func (i ItemInfo) infoType() ItemType {
 	return UnknownType
 }
 
+func (i ItemInfo) size() int64 {
+	switch {
+	case i.Exchange != nil:
+		return i.Exchange.Size
+
+	case i.OneDrive != nil:
+		return i.OneDrive.Size
+
+	case i.SharePoint != nil:
+		return i.SharePoint.Size
+
+	case i.Folder != nil:
+		return i.Folder.Size
+	}
+
+	return 0
+}
+
+func (i ItemInfo) modified() time.Time {
+	switch {
+	case i.Exchange != nil:
+		return i.Exchange.Modified
+
+	case i.OneDrive != nil:
+		return i.OneDrive.Modified
+
+	case i.SharePoint != nil:
+		return i.SharePoint.Modified
+
+	case i.Folder != nil:
+		return i.Folder.Modified
+	}
+
+	return time.Time{}
+}
+
 type FolderInfo struct {
 	ItemType    ItemType  `json:"itemType,omitempty"`
 	DisplayName string    `json:"displayName"`

src/pkg/backup/details/details_test.go

@@ -341,7 +341,6 @@ func (suite *DetailsUnitSuite) TestDetails_AddFolders() {
 
 func (suite *DetailsUnitSuite) TestDetails_AddFoldersDifferentServices() {
 	itemTime := time.Date(2022, 10, 21, 10, 0, 0, 0, time.UTC)
-	folderTimeOlderThanItem := time.Date(2022, 9, 21, 10, 0, 0, 0, time.UTC)
 
 	table := []struct {
 		name               string
@@ -395,9 +394,7 @@ func (suite *DetailsUnitSuite) TestDetails_AddFoldersDifferentServices() {
 				ShortRef:  "sr1",
 				ParentRef: "pr1",
 				Info: details.ItemInfo{
-					Folder: &details.FolderInfo{
-						Modified: folderTimeOlderThanItem,
-					},
+					Folder: &details.FolderInfo{},
 				},
 			}