Enable test

Author: blegat

test/monovec.jl

@@ -3,7 +3,7 @@
     @test x > y
     @test x^2 > y^2
     X = [x^2, x*y, y^2]
-    #@test isempty(@inferred monomials((x, y), 1:0))
+    @test isempty(@inferred monomials((x, y), 1:0))
     for (i, m) in enumerate(monomials((x, y), 2))
         @test m == X[i]
     end