Add tests

Author: gdalle

DifferentiationInterface/test/Back/Enzyme/hints.jl

@@ -0,0 +1,56 @@
+using DifferentiationInterface
+using Enzyme: Enzyme
+using Test
+
+@testset "MutabilityError" begin
+    f = let
+        cache = [0.0]
+        x -> sum(copyto!(cache, x))
+    end
+
+    msg = try
+        gradient(f, AutoEnzyme(), [1.0])
+    catch e
+        buf = IOBuffer()
+        showerror(buf, e)
+        String(take!(buf))
+    end
+    @test occursin("AutoEnzyme", msg)
+    @test occursin("function_annotation", msg)
+    @test occursin("ADTypes", msg)
+    @test occursin("DifferentiationInterface", msg)
+end
+
+@testset "RuntimeActivityError" begin
+    function g(active_var, constant_var, cond)
+        if cond
+            return active_var
+        else
+            return constant_var
+        end
+    end
+
+    function h(active_var, constant_var, cond)
+        return [g(active_var, constant_var, cond), g(active_var, constant_var, cond)]
+    end
+
+    msg = try
+        pushforward(
+            h,
+            AutoEnzyme(; mode=Enzyme.Forward),
+            [1.0],
+            ([1.0],),
+            Constant([1.0]),
+            Constant(true),
+        )
+    catch e
+        buf = IOBuffer()
+        showerror(buf, e)
+        String(take!(buf))
+    end
+    @test occursin("AutoEnzyme", msg)
+    @test occursin("mode", msg)
+    @test occursin("set_runtime_activity", msg)
+    @test occursin("ADTypes", msg)
+    @test occursin("DifferentiationInterface", msg)
+end

DifferentiationInterface/test/Core/Internals/hints.jl

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+using ADTypes
+using DifferentiationInterface
+import DifferentiationInterface as DI
+using Test
+
+@testset "Missing backend" begin
+    msg = try
+        gradient(sum, AutoZygote(), [1.0])
+    catch e
+        buf = IOBuffer()
+        showerror(buf, e)
+        String(take!(buf))
+    end
+    @test occursin("import Zygote", msg)
+end