Remove obsolete gRPC client/server implementations and migrate to remote package

manager_test.go

@@ -554,3 +554,60 @@ func TestUpdateSnapshotMetadata(t *testing.T) {
 		t.Fatalf("Expected error when updating non-existent snapshot, got nil")
 	}
 }
+
+func TestStreamSnapshotDiff_EdgeCases(t *testing.T) {
+	tempDir, metadataStore, blobStore, cleanup := setupTestEnvironment(t)
+	defer cleanup()
+
+	sourceDir := filepath.Join(tempDir, "source")
+	os.MkdirAll(sourceDir, 0755)
+	createTestFiles(t, sourceDir)
+
+	manager, err := CreateSnapshotManager(metadataStore, blobStore, nil)
+	if err != nil {
+		t.Fatalf("Failed to create snapshot manager: %v", err)
+	}
+	ctx := context.Background()
+
+	// Create two identical snapshots
+	snap1, _ := manager.CreateSnapshot(ctx, sourceDir, "Snap1", "")
+	snap2, _ := manager.CreateSnapshot(ctx, sourceDir, "Snap2", snap1.ID)
+
+	// Test 1: Diff between identical snapshots should be empty
+	reader, err := manager.StreamSnapshotDiff(ctx, snap2.ID, snap1.ID, 0)
+	if err != nil {
+		t.Fatalf("Expected no error for identical snapshots, got %v", err)
+	}
+	defer reader.Close()
+	data, _ := io.ReadAll(reader)
+	if len(data) != 0 {
+		t.Errorf("Expected empty diff for identical snapshots, got %d bytes", len(data))
+	}
+
+	// Test 2: Diff with a non-existent parent should be a full archive
+	reader, err = manager.StreamSnapshotDiff(ctx, snap1.ID, "non-existent-parent", 0)
+	if err != nil {
+		t.Fatalf("Expected no error for non-existent parent, got %v", err)
+	}
+	defer reader.Close()
+	data, _ = io.ReadAll(reader)
+	if len(data) == 0 {
+		t.Error("Expected full archive for non-existent parent, got empty diff")
+	}
+
+	// Create an empty source dir
+	emptyDir := filepath.Join(tempDir, "empty_source")
+	os.MkdirAll(emptyDir, 0755)
+	emptySnap, _ := manager.CreateSnapshot(ctx, emptyDir, "EmptySnap", "")
+
+	// Test 3: Diff of an empty snapshot should be empty
+	reader, err = manager.StreamSnapshotDiff(ctx, emptySnap.ID, "", 0)
+	if err != nil {
+		t.Fatalf("Expected no error for empty snapshot, got %v", err)
+	}
+	defer reader.Close()
+	data, _ = io.ReadAll(reader)
+	if len(data) != 0 {
+		t.Errorf("Expected empty diff for empty snapshot, got %d bytes", len(data))
+	}
+}