Add trivial tests for binary operations involving two TaylorScalar

Author: facusapienza21

test/primitive.jl

@@ -50,6 +50,12 @@ end
     # end
 end
 
+@testset "Multi-argument functions" begin 
+    @test derivative(x -> 1 + 1/x, 1.0, Val(1))≈-1.0 rtol=1e-6
+    @test derivative(x -> (x+1)/x, 1.0, Val(1))≈-1.0 rtol=1e-6
+    @test derivative(x -> x/x, 1.0, Val(1))≈ 0.0 rtol=1e-6
+end
+
 @testset "Corner cases" begin
     offenders = (
         TaylorScalar(Inf, (1.0, 0.0, 0.0)),