Thanks for the link! @testset macro will be very useful here.
Could you tell me how did you end up with the line 48? Based on the stack trace, as I see it, the other line is to blame:
[4] top-level scope @ ~/work/FluxExtra.jl/FluxExtra.jl/test/runtests.jl:142
which tests the activation layer:
[3] test(model::Chain{Tuple{Conv{2, 4, typeof(identity), Array{Float32, 4}, Vector{Float32}}, Activation{typeof(tanh)}}}, x::Array{Float32, 4}, y::Array{Float32, 4}) @ Main ~/work/FluxExtra.jl/FluxExtra.jl/test/runtests.jl:35