Fix Project.toml

Oops, accidentally removed fdm test

Author: YingboMa

Project.toml

@@ -10,8 +10,6 @@ Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]
-Reexport = "0.2"
-Requires = "0.5.2"
 ChainRulesCore = "0.5"
 FiniteDifferences = "^0.7"
 Reexport = "0.2"

test/test_util.jl

@@ -33,6 +33,8 @@ function test_scalar(f, x; rtol=1e-9, atol=1e-9, fdm=_fdm, kwargs...)
             ∂self, ∂x = ∂x
             @test ∂self === NO_FIELDS
         end
+        @test isapprox(∂x, fdm(f, x);
+                       rtol=rtol, atol=atol, kwargs...)
     end
 end