diff --git a/driver/savepoint.go b/driver/savepoint.go
index 60aa6b9..eea40dd 100644
--- a/driver/savepoint.go
+++ b/driver/savepoint.go
@@ -16,12 +16,25 @@ func Savepoint(tx *sql.Tx) sqlite3.Savepoint {
 	return ctx.Savepoint
 }
 
+// A saveptCtx is never canceled, has no values, and has no deadline.
 type saveptCtx struct{ sqlite3.Savepoint }
 
-func (*saveptCtx) Deadline() (deadline time.Time, ok bool) { return }
+func (*saveptCtx) Deadline() (deadline time.Time, ok bool) {
+	// notest
+	return
+}
 
-func (*saveptCtx) Done() <-chan struct{} { return nil }
+func (*saveptCtx) Done() <-chan struct{} {
+	// notest
+	return nil
+}
 
-func (*saveptCtx) Err() error { return nil }
+func (*saveptCtx) Err() error {
+	// notest
+	return nil
+}
 
-func (*saveptCtx) Value(key any) any { return nil }
+func (*saveptCtx) Value(key any) any {
+	// notest
+	return nil
+}
diff --git a/ext/bloom/bloom.go b/ext/bloom/bloom.go
index cda142d..85d3879 100644
--- a/ext/bloom/bloom.go
+++ b/ext/bloom/bloom.go
@@ -160,7 +160,9 @@ func (b *bloom) Rename(new string) error {
 	return err
 }
 
-func (t *bloom) ShadowTables() {}
+func (t *bloom) ShadowTables() {
+	// notest // not meant to be called
+}
 
 func (t *bloom) Integrity(schema, table string, flags int) error {
 	load, _, err := t.db.Prepare(fmt.Sprintf(
diff --git a/internal/alloc/alloc_test.go b/internal/alloc/alloc_test.go
new file mode 100644
index 0000000..e41b8fb
--- /dev/null
+++ b/internal/alloc/alloc_test.go
@@ -0,0 +1,14 @@
+package alloc_test
+
+import (
+	"math"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/internal/alloc"
+)
+
+func TestVirtual(t *testing.T) {
+	defer func() { _ = recover() }()
+	alloc.Virtual(math.MaxInt+2, math.MaxInt+2)
+	t.Error("want panic")
+}
diff --git a/internal/testcfg/testcfg.go b/internal/testcfg/testcfg.go
index 23e0d3b..f1b07f8 100644
--- a/internal/testcfg/testcfg.go
+++ b/internal/testcfg/testcfg.go
@@ -9,6 +9,8 @@ import (
 	"github.com/tetratelabs/wazero"
 )
 
+// notest
+
 func init() {
 	if bits.UintSize < 64 {
 		return
diff --git a/vfs/memdb/memdb.go b/vfs/memdb/memdb.go
index f21335d..027fb7f 100644
--- a/vfs/memdb/memdb.go
+++ b/vfs/memdb/memdb.go
@@ -30,6 +30,7 @@ func (memVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, err
 		vfs.OPEN_TEMP_DB |
 		vfs.OPEN_TEMP_JOURNAL
 	if flags&types == 0 {
+		// notest
 		return nil, flags, sqlite3.CANTOPEN
 	}
 
@@ -136,7 +137,7 @@ func (m *memFile) ReadAt(b []byte, off int64) (n int, err error) {
 	}
 	n = copy(b, (*m.data[base])[rest:have])
 	if n < len(b) {
-		// Assume reads are page aligned.
+		// notest // assume reads are page aligned
 		return 0, io.ErrNoProgress
 	}
 	return n, nil
@@ -153,7 +154,7 @@ func (m *memFile) WriteAt(b []byte, off int64) (n int, err error) {
 	}
 	n = copy((*m.data[base])[rest:], b)
 	if n < len(b) {
-		// Assume writes are page aligned.
+		// notest // assume writes are page aligned
 		return n, io.ErrShortWrite
 	}
 	if size := off + int64(len(b)); size > m.size {
diff --git a/vfs/os_f2fs_linux.go b/vfs/os_f2fs_linux.go
index a9f0e33..487f0c7 100644
--- a/vfs/os_f2fs_linux.go
+++ b/vfs/os_f2fs_linux.go
@@ -16,6 +16,8 @@ const (
 	_F2FS_FEATURE_ATOMIC_WRITE    = 4
 )
 
+// notest
+
 func osBatchAtomic(file *os.File) bool {
 	flags, err := unix.IoctlGetInt(int(file.Fd()), _F2FS_IOC_GET_FEATURES)
 	return err == nil && flags&_F2FS_FEATURE_ATOMIC_WRITE != 0
diff --git a/vfs/readervfs/reader.go b/vfs/readervfs/reader.go
index 15b9471..3614c64 100644
--- a/vfs/readervfs/reader.go
+++ b/vfs/readervfs/reader.go
@@ -10,6 +10,7 @@ type readerVFS struct{}
 
 func (readerVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
 	if flags&vfs.OPEN_MAIN_DB == 0 {
+		// notest
 		return nil, flags, sqlite3.CANTOPEN
 	}
 	readerMtx.RLock()
@@ -21,10 +22,12 @@ func (readerVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag,
 }
 
 func (readerVFS) Delete(name string, dirSync bool) error {
+	// notest
 	return sqlite3.IOERR_DELETE
 }
 
 func (readerVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
+	// notest
 	return false, nil
 }
 
@@ -39,30 +42,37 @@ func (readerFile) Close() error {
 }
 
 func (readerFile) WriteAt(b []byte, off int64) (n int, err error) {
+	// notest
 	return 0, sqlite3.READONLY
 }
 
 func (readerFile) Truncate(size int64) error {
+	// notest
 	return sqlite3.READONLY
 }
 
 func (readerFile) Sync(flag vfs.SyncFlag) error {
+	// notest
 	return nil
 }
 
 func (readerFile) Lock(lock vfs.LockLevel) error {
+	// notest
 	return nil
 }
 
 func (readerFile) Unlock(lock vfs.LockLevel) error {
+	// notest
 	return nil
 }
 
 func (readerFile) CheckReservedLock() (bool, error) {
+	// notest
 	return false, nil
 }
 
 func (readerFile) SectorSize() int {
+	// notest
 	return 0
 }