Test ChainRules integration directly

Update test/chainrules.jl

Update test/chainrules.jl

test/chainrules.jl

@@ -0,0 +1,49 @@
+using Zygote, Test, ChainRules
+
+const cr_inner_demo_rrule_hitcount = Ref(0)
+const cr_inner_demo_pullback_hitcount = Ref(0)
+cr_inner_demo(x) = 5x
+function ChainRules.rrule(::typeof(cr_inner_demo), x)
+    cr_inner_demo_rrule_hitcount[] += 1
+    function cr_inner_demo_pullback(Δx)
+        cr_inner_demo_pullback_hitcount[] += 1
+        return ChainRules.NO_FIELDS, 5.0*Δx
+    end
+    return cr_inner_demo(x), cr_inner_demo_pullback
+end
+
+function cr_outer_demo(x)
+    2 + 10cr_inner_demo(x)
+end
+
+@testset "ChainRules Integration" begin
+    @testset "gradient inner" begin
+        cr_inner_demo_rrule_hitcount[] = 0
+        cr_inner_demo_pullback_hitcount[] = 0
+        @test (5.0,) == gradient(cr_inner_demo, 11)
+        @test cr_inner_demo_rrule_hitcount[] == 1
+        @test cr_inner_demo_pullback_hitcount[] == 1
+    end
+
+    @testset "gradient outer" begin
+        cr_inner_demo_rrule_hitcount[] = 0
+        cr_inner_demo_pullback_hitcount[] = 0
+        @test (50.0,) == gradient(cr_outer_demo, 11)
+        @test cr_inner_demo_rrule_hitcount[] == 1
+        @test cr_inner_demo_pullback_hitcount[] == 1
+    end
+
+    @testset "pullback inner" begin
+        cr_inner_demo_rrule_hitcount[] = 0
+        cr_inner_demo_pullback_hitcount[] = 0
+        y, pb = pullback(cr_inner_demo, 11)
+        @test y == 55
+        @test cr_inner_demo_rrule_hitcount[] == 1
+        @test cr_inner_demo_pullback_hitcount[] == 0
+        @test pb(1)==(5.0,);
+        @test pb(2)==(10.0,);
+        @test pb(3)==(15.0,);
+        @test cr_inner_demo_pullback_hitcount[] == 3
+        @test cr_inner_demo_rrule_hitcount[] == 1
+    end
+end

test/runtests.jl

@@ -15,6 +15,12 @@ end
   include("structures.jl")
 end
 
+@info "Testing ChainRules integration"
+
+@testset "ChainRules" begin
+  include("chainrules.jl")
+end
+
 @info "Running Gradient Checks"
 
 @testset "Gradients" begin