Test error is thrown for unsupported functions

Author: MilesCranmer

src/base.jl

@@ -297,18 +297,10 @@ function convert(
 end
 (::Type{Node{T}})(tree::Node; kws...) where {T} = convert(Node{T}, tree; kws...)
 
-function reduce(f, tree::Node; init=nothing)
-    throw(ArgumentError("reduce is not supported for trees. Use tree_mapreduce instead."))
-end
-function foldl(f, tree::Node; init=nothing)
-    throw(ArgumentError("foldl is not supported for trees. Use tree_mapreduce instead."))
-end
-function foldr(f, tree::Node; init=nothing)
-    throw(ArgumentError("foldr is not supported for trees. Use tree_mapreduce instead."))
-end
-function mapfoldl(f, tree::Node; init=nothing)
-    throw(ArgumentError("mapfoldl is not supported for trees. Use tree_mapreduce instead."))
-end
-function mapfoldr(f, tree::Node; init=nothing)
-    throw(ArgumentError("mapfoldr is not supported for trees. Use tree_mapreduce instead."))
+for func in (:reduce, :foldl, :foldr, :mapfoldl, :mapfoldr)
+    @eval begin
+        function $func(f, tree::Node; kws...)
+            throw(error(string($func) * " not implemented for Node. Use `tree_mapreduce` instead."))
+        end
+    end
 end

test/test_base.jl

@@ -163,3 +163,10 @@ end
     end
     @test sum(t -> (t.degree == 0 && t.constant) ? t.val : 0.0, ctree) ≈ 11.6 * 1.5
 end
+
+@testset "Unsupported" begin
+    for func in (:reduce, :foldl, :foldr, :mapfoldl, :mapfoldr)
+        wrapped_func(args...) = (@eval $func)(args...)
+        @test_throws ErrorException wrapped_func(Returns(1), tree)
+    end
+end