Add tests for prefetch streamItems

src/internal/m365/collection/groups/collection.go

@@ -180,9 +180,8 @@ func (col *prefetchCollection[C, I]) streamItems(ctx context.Context, errs *faul
 			defer func() { <-semaphoreCh }()
 
 			// This is a no-op for conversations, as there is no way to detect
-			// deleted items in a conversation. It might be added in the future
-			// if graph supports it, so make sure we put up both .data and .meta
-			// files for deletions.
+			// deleted items. It might be added in future if graph supports it,
+			// so make sure we put up both .data and .meta files for deletions.
 			if col.getAndAugment.supportsItemMetadata() {
 				col.stream <- data.NewDeletedItem(id + metadata.DataFileSuffix)
 				col.stream <- data.NewDeletedItem(id + metadata.MetaFileSuffix)

src/internal/m365/collection/groups/collection_test.go

@@ -185,7 +185,8 @@ func (getAndAugmentChannelMessage) supportsItemMetadata() bool {
 	return false
 }
 
-func (suite *CollectionUnitSuite) TestPrefetchCollection_streamItems() {
+// Test prefetch streamItems() for channel messages.
+func (suite *CollectionUnitSuite) TestPrefetchCollection_ChannelMessages() {
 	var (
 		t             = suite.T()
 		start         = time.Now().Add(-1 * time.Second)
@@ -264,6 +265,11 @@ func (suite *CollectionUnitSuite) TestPrefetchCollection_streamItems() {
 			go col.streamItems(ctx, errs)
 
 			for item := range col.stream {
+				// Make sure item IDs don't have .data and .meta suffixes.
+				// Those are only meant for conversations.
+				assert.False(t, strings.HasSuffix(item.ID(), ".data"))
+				assert.False(t, strings.HasSuffix(item.ID(), ".meta"))
+
 				itemCount++
 
 				_, aok := test.added[item.ID()]
@@ -292,6 +298,161 @@ func (suite *CollectionUnitSuite) TestPrefetchCollection_streamItems() {
 	}
 }
 
+// Test prefetch streamItems() for conversations.
+func (suite *CollectionUnitSuite) TestPrefetchCollection_Conversations() {
+	var (
+		t             = suite.T()
+		start         = time.Now().Add(-1 * time.Second)
+		statusUpdater = func(*support.ControllerOperationStatus) {}
+	)
+
+	fullPath, err := path.Build("t", "pr", path.GroupsService, path.ConversationPostsCategory, false, "f", "s")
+	require.NoError(t, err, clues.ToCore(err))
+
+	locPath, err := path.Build("t", "pr", path.GroupsService, path.ConversationPostsCategory, false, "f", "s")
+	require.NoError(t, err, clues.ToCore(err))
+
+	table := []struct {
+		name    string
+		added   map[string]time.Time
+		removed map[string]struct{}
+	}{
+		{
+			name: "no items",
+		},
+		{
+			name: "only added items",
+			added: map[string]time.Time{
+				"fisher":    {},
+				"flannigan": {},
+				"fitzbog":   {},
+			},
+		},
+		{
+			name: "only removed items",
+			removed: map[string]struct{}{
+				"princess": {},
+				"poppy":    {},
+				"petunia":  {},
+			},
+		},
+		{
+			name: "added and removed items",
+			added: map[string]time.Time{
+				"goblin": {},
+			},
+			removed: map[string]struct{}{
+				"general":  {},
+				"goose":    {},
+				"grumbles": {},
+			},
+		},
+	}
+	for _, test := range table {
+		suite.Run(test.name, func() {
+			var (
+				t         = suite.T()
+				errs      = fault.New(true)
+				itemCount int
+				itemMap   = map[string]data.Item{}
+			)
+
+			ctx, flush := tester.NewContext(t)
+			defer flush()
+
+			col := &prefetchCollection[models.Conversationable, models.Postable]{
+				BaseCollection: data.NewBaseCollection(
+					fullPath,
+					nil,
+					locPath.ToBuilder(),
+					control.DefaultOptions(),
+					false,
+					count.New()),
+				added:         test.added,
+				contains:      container[models.Conversationable]{},
+				removed:       test.removed,
+				getAndAugment: &getAndAugmentConversation{},
+				stream:        make(chan data.Item),
+				statusUpdater: statusUpdater,
+			}
+
+			go col.streamItems(ctx, errs)
+
+			for item := range col.stream {
+				var trimmedID string
+
+				switch {
+				case strings.HasSuffix(item.ID(), ".data"):
+					trimmedID = strings.TrimSuffix(item.ID(), ".data")
+				case strings.HasSuffix(item.ID(), ".meta"):
+					trimmedID = strings.TrimSuffix(item.ID(), ".meta")
+				default:
+					assert.Fail(t, "unexpected item suffix: %s", item.ID())
+				}
+
+				itemCount++
+				itemMap[item.ID()] = item
+
+				_, aok := test.added[trimmedID]
+				if aok {
+					assert.False(t, item.Deleted(), "additions should not be marked as deleted")
+				}
+
+				_, rok := test.removed[trimmedID]
+				if rok {
+					assert.True(t, item.Deleted(), "removals should be marked as deleted")
+					dimt, ok := item.(data.ItemModTime)
+					require.True(t, ok, "item implements data.ItemModTime")
+					assert.True(t, dimt.ModTime().After(start), "deleted items should set mod time to now()")
+				}
+
+				assert.True(t, aok || rok, "item must be either added or removed: %q", item.ID())
+			}
+
+			assert.NoError(t, errs.Failure())
+			assert.Equal(
+				t,
+				2*(len(test.added)+len(test.removed)),
+				itemCount,
+				"should see all expected items")
+
+			addedAndRemoved := append(maps.Keys(test.added), maps.Keys(test.removed)...)
+			for _, id := range addedAndRemoved {
+				// Should have a .data and a .meta file
+				d, ok := itemMap[id+".data"]
+				assert.True(t, ok, "should have data file for %q", id)
+
+				m, ok := itemMap[id+".meta"]
+				assert.True(t, ok, "should have meta file for %q", id)
+
+				// Meta files should not have item info.
+				assert.Implements(t, (*data.Item)(nil), m)
+
+				if slices.Contains(maps.Keys(test.removed), id) {
+					continue
+				}
+
+				// Mod times should match. Not doing this check for removed items
+				// since mod time is set to now() for them.
+				assert.Equal(
+					t,
+					d.(data.ItemModTime).ModTime(),
+					m.(data.ItemModTime).ModTime(),
+					"item mod time")
+
+				// Read meta file data. The data is of no significance, we just want
+				// to make sure the file is readable.
+				r := m.ToReader()
+
+				_, err := io.ReadAll(r)
+				assert.NoError(t, err, clues.ToCore(err))
+
+				r.Close()
+			}
+		})
+	}
+}
+
 type getAndAugmentConversation struct {
 	GetItemErr error
 	GetMetaErr error
@@ -341,6 +502,7 @@ func (m *getAndAugmentConversation) check(t *testing.T, expected []string) {
 	assert.Equal(t, expected, m.CallIDs, "expected calls")
 }
 
+// Test lazy streamItems() for conversations.
 func (suite *CollectionUnitSuite) TestLazyFetchCollection_Conversations() {
 	var (
 		t             = suite.T()