diff --git a/revid/revid_test.go b/revid/revid_test.go
index 867ded78..ccf0de3a 100644
--- a/revid/revid_test.go
+++ b/revid/revid_test.go
@@ -97,10 +97,10 @@ func (e *tstFlvEncoder) Write(d []byte) (int, error) { return len(d), nil }
 // dummyMultiWriter emulates the MultiWriter provided by std lib, so that we
 // can access the destinations.
 type dummyMultiWriter struct {
-	dst []io.Writer
+	dst []io.WriteCloser
 }
 
-func newDummyMultiWriter(dst ...io.Writer) io.Writer {
+func newDummyMultiWriter(dst ...io.WriteCloser) io.WriteCloser {
 	return &dummyMultiWriter{
 		dst: dst,
 	}
@@ -108,6 +108,8 @@ func newDummyMultiWriter(dst ...io.Writer) io.Writer {
 
 func (w *dummyMultiWriter) Write(d []byte) (int, error) { return len(d), nil }
 
+func (w *dummyMultiWriter) Close() error { return nil }
+
 // TestResetEncoderSenderSetup checks that revid.reset() correctly sets up the
 // revid.encoder slice and the senders the encoders write to.
 func TestResetEncoderSenderSetup(t *testing.T) {