disable forward mode testing

Author: penelopeysm

ext/BijectorsMooncakeExt.jl

@@ -15,6 +15,7 @@ using Bijectors: find_alpha, ChainRulesCore
 # unusual Integer type is encountered.
 @is_primitive(MinimalCtx, Tuple{typeof(find_alpha),P,P,Integer} where {P<:Base.IEEEFloat})
 
+# TODO: This needs a corresponding frule!! as well for it to work on forward-mode Mooncake.
 function Mooncake.rrule!!(
     ::CoDual{typeof(find_alpha)}, x::CoDual{P}, y::CoDual{P}, z::CoDual{I}
 ) where {P<:Base.IEEEFloat,I<:Integer}

test/ad/chainrules.jl

@@ -31,7 +31,8 @@ end
 
     if @isdefined Mooncake
         rng = Xoshiro(123456)
-        @testset "$mode" for mode in (Mooncake.ForwardMode, Mooncake.ReverseMode)
+        # TODO: Enable Mooncake.ForwardMode as well.
+        @testset "$mode" for mode in (Mooncake.ReverseMode,)
             Mooncake.TestUtils.test_rule(
                 rng,
                 Bijectors.find_alpha,