# Do I have to implement Flux.testmode! for my own models?
**URL:** https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038
**Category:** Machine Learning
**Created:** [December 18, 2020, 11:21am UTC](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038 "2020-12-18T11:21:22Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@maxfreu](https://discourse.julialang.org/u/maxfreu)
#### Post date: [December 18, 2020, 11:21am UTC](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038/1 "2020-12-18T11:21:22Z")
Hi, I implemented a U-Net and would like to switch between train and test mode for the BN layers.
```julia
struct Unet
encoder # tuple of chains
decoder # tuple of UpBlocks
segmentation_head # normal conv layer
end
Flux.@functor Unet
...
```
As of now `testmode!(unet)` just returns the input with nothing changed. Do I have to manually implement it for the building blocks and the model itself or is there some smart way to circumvent this? Some models are simply not a `Chain` in their structure…
Edit: By chance I found [this](https://github.com/FluxML/Flux.jl/issues/1429) issue, which suggests that I have to do so. Can the user somehow be warned if testmode! changes nothing?
---
### Author:  [@ToucheSir](https://discourse.julialang.org/u/ToucheSir)
#### Post date: [December 18, 2020, 6:00pm UTC](https://discourse.julialang.org/t/do-i-have-to-implement-flux-testmode-for-my-own-models/52038/2 "2020-12-18T18:00:58Z")
As I mentioned on the issue thread, the straightforward fix would be to recurse via `trainable` in `testmode!` so that it automatically works with functors. However, this would mean that most of the recursive calls are no-ops, so warning on them would likely generate a great deal of superfluous warnings.