diff --git a/tests/db_test.go b/tests/db_test.go
index ed89bf1..0ac50f8 100644
--- a/tests/db_test.go
+++ b/tests/db_test.go
@@ -16,10 +16,10 @@ import (
 )
 
 //go:embed testdata/wal.db
-var waldb []byte
+var walDB []byte
 
 //go:embed testdata/utf16be.db
-var utf16db []byte
+var utf16DB []byte
 
 func TestDB_memory(t *testing.T) {
 	t.Parallel()
@@ -42,7 +42,7 @@ func TestDB_wal(t *testing.T) {
 
 	t.Parallel()
 	tmp := filepath.Join(t.TempDir(), "test.db")
-	err := os.WriteFile(tmp, waldb, 0666)
+	err := os.WriteFile(tmp, walDB, 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -56,7 +56,7 @@ func TestDB_utf16(t *testing.T) {
 
 	t.Parallel()
 	tmp := filepath.Join(t.TempDir(), "test.db")
-	err := os.WriteFile(tmp, utf16db, 0666)
+	err := os.WriteFile(tmp, utf16DB, 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/tests/wal_test.go b/tests/wal_test.go
index 017ed57..15fd92d 100644
--- a/tests/wal_test.go
+++ b/tests/wal_test.go
@@ -26,7 +26,7 @@ func TestWAL_enter_exit(t *testing.T) {
 	defer db.Close()
 
 	if !vfs.SupportsSharedMemory {
-		err = db.Exec(`PRAGMA locking_mode=EXCLUSIVE`)
+		err = db.Exec(`PRAGMA locking_mode=exclusive`)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -34,11 +34,11 @@ func TestWAL_enter_exit(t *testing.T) {
 
 	err = db.Exec(`
 		CREATE TABLE test (col);
-		PRAGMA journal_mode=WAL;
+		PRAGMA journal_mode=wal;
 		SELECT * FROM test;
-		PRAGMA journal_mode=DELETE;
+		PRAGMA journal_mode=delete;
 		SELECT * FROM test;
-		PRAGMA journal_mode=WAL;
+		PRAGMA journal_mode=wal;
 		SELECT * FROM test;
 	`)
 	if err != nil {
@@ -53,7 +53,7 @@ func TestWAL_readonly(t *testing.T) {
 	t.Parallel()
 
 	tmp := filepath.Join(t.TempDir(), "test.db")
-	err := os.WriteFile(tmp, waldb, 0666)
+	err := os.WriteFile(tmp, walDB, 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -101,8 +101,8 @@ func TestConn_WalCheckpoint(t *testing.T) {
 	})
 
 	err = db.Exec(`
-		PRAGMA locking_mode=EXCLUSIVE;
-		PRAGMA journal_mode=WAL;
+		PRAGMA locking_mode=exlusive;
+		PRAGMA journal_mode=wal;
 		CREATE TABLE test (col);
 	`)
 	if err != nil {
diff --git a/vfs/adiantum/adiantum_test.go b/vfs/adiantum/adiantum_test.go
index e13ff74..2b8c8fe 100644
--- a/vfs/adiantum/adiantum_test.go
+++ b/vfs/adiantum/adiantum_test.go
@@ -1,14 +1,48 @@
 package adiantum_test
 
 import (
+	_ "embed"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
-	_ "github.com/ncruces/go-sqlite3/vfs/adiantum"
+	"github.com/ncruces/go-sqlite3/util/ioutil"
+	"github.com/ncruces/go-sqlite3/vfs"
+	"github.com/ncruces/go-sqlite3/vfs/adiantum"
+	"github.com/ncruces/go-sqlite3/vfs/readervfs"
 )
 
+//go:embed testdata/test.db
+var testDB string
+
+func Test_fileformat(t *testing.T) {
+	readervfs.Create("test.db", ioutil.NewSizeReaderAt(strings.NewReader(testDB)))
+	adiantum.Register("adiantum", vfs.Find("reader"), nil)
+
+	db, err := driver.Open("file:test.db?vfs=adiantum", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	_, err = db.Exec(`PRAGMA textkey='correct+horse+battery+staple'`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var version uint32
+	err = db.QueryRow(`PRAGMA user_version`).Scan(&version)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if version != 0xBADDB {
+		t.Error(version)
+	}
+}
+
 func Benchmark_nokey(b *testing.B) {
 	tmp := filepath.Join(b.TempDir(), "test.db")
 	sqlite3.Initialize()
diff --git a/vfs/adiantum/testdata/test.db b/vfs/adiantum/testdata/test.db
new file mode 100644
index 0000000..3f8ac93
Binary files /dev/null and b/vfs/adiantum/testdata/test.db differ