feat(mockfs): add DumpDB method

server/mockfs/mockfs.go

@@ -1,14 +1,17 @@
 package mockfs
 
 import (
+	"context"
 	"errors"
 	"fmt"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/mattn/go-sqlite3"
 	"go.senan.xyz/gonic/server/db"
 	"go.senan.xyz/gonic/server/scanner"
 	"go.senan.xyz/gonic/server/scanner/tags"
@@ -246,6 +249,55 @@ func (m *MockFS) SetTags(path string, cb func(*Tags)) {
 	cb(m.reader.tags[abspath])
 }
 
+func (m *MockFS) DumpDB(suffix ...string) {
+	var p []string
+	p = append(p,
+		"gonic", "dump",
+		strings.ReplaceAll(m.t.Name(), string(filepath.Separator), "-"),
+		fmt.Sprint(time.Now().UnixNano()),
+	)
+	p = append(p, suffix...)
+
+	destPath := filepath.Join(os.TempDir(), strings.Join(p, "-"))
+	dest, err := db.New(destPath, url.Values{})
+	if err != nil {
+		m.t.Fatalf("create dest db: %v", err)
+	}
+	defer dest.Close()
+
+	connSrc, err := m.db.DB.DB().Conn(context.Background())
+	if err != nil {
+		m.t.Fatalf("getting src raw conn: %v", err)
+	}
+	defer connSrc.Close()
+	connDest, err := dest.DB.DB().Conn(context.Background())
+	if err != nil {
+		m.t.Fatalf("getting dest raw conn: %v", err)
+	}
+	defer connDest.Close()
+
+	err = connDest.Raw(func(connDest interface{}) error {
+		return connSrc.Raw(func(connSrc interface{}) error {
+			connDestq := connDest.(*sqlite3.SQLiteConn)
+			connSrcq := connSrc.(*sqlite3.SQLiteConn)
+			bk, err := connDestq.Backup("main", connSrcq, "main")
+			if err != nil {
+				return fmt.Errorf("create backup db: %w", err)
+			}
+			for done, _ := bk.Step(-1); !done; {
+				m.t.Logf("dumping db...")
+			}
+			if err := bk.Finish(); err != nil {
+				return fmt.Errorf("finishing dump: %w", err)
+			}
+			return nil
+		})
+	})
+	if err != nil {
+		m.t.Fatalf("backing up: %v", err)
+	}
+}
+
 type mreader struct {
 	tags map[string]*Tags
 }