Fix tests

Dockerfile

 EXPOSE 3128 3129
 
 COPY --from=0 /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
-COPY --from=0 /go/src/github.com/9seconds/mtg /usr/local/bin/mtg
+COPY --from=0 /go/src/github.com/9seconds/mtg/mtg /usr/local/bin/mtg

obfuscated2/frame_test.go

 }
 
 func TestFrameDC(t *testing.T) {
-	assert.Equal(t, int16(771), makeFrame().DC())
+	assert.Equal(t, int16(770), makeFrame().DC())
 }
 
 func TestFrameValid(t *testing.T) {
 	assert.False(t, frame.Valid())
 }
 
+func TestFrameDoubleInvert(t *testing.T) {
+	frame := makeFrame()
+	assert.Equal(t, frame, frame.Invert().Invert())
+}
+
 func TestFrameInvert(t *testing.T) {
 	frame := makeFrame()
 	reversed := frame.Invert()