diff --git a/test/runtests.jl b/test/runtests.jl
index 533cf93..c27fdd0 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -45,7 +45,11 @@ for (M, f, arity) in DiffRules.diffrules(; filter_modules=nothing)
         derivs = DiffRules.diffrule(M, f, :foo, :bar)
         @eval begin
             let
-                foo, bar = rand(1:10), rand()
+                if "mod" == string($M.$f)
+                    foo, bar = rand() + 13, rand() + 5 # make sure x/y is not integer
+                else
+                    foo, bar = rand(1:10), rand()
+                end
                 dx, dy = $(derivs[1]), $(derivs[2])
                 if !(isnan(dx))
                     @test isapprox(dx, finitediff(z -> $M.$f(z, bar), float(foo)), rtol=0.05)