Error for divides with noncommutative (#154)

Author: blegat

src/div.jl

@@ -1,4 +1,7 @@
-function MP.divides(m1::Monomial, m2::Monomial)
+function MP.divides(m1::Monomial{<:NonCommutative}, m2::Monomial{<:NonCommutative})
+    error("Not implemented yet")
+end
+function MP.divides(m1::Monomial{<:Commutative}, m2::Monomial{<:Commutative})
     e1 = exponents(m1)
     v1 = variables(m1)
     e2 = exponents(m2)

test/mono.jl

@@ -166,4 +166,9 @@ import MultivariatePolynomials as MP
         @test filter(mono -> degree(mono) == 1, X) == monomial_vector([x, y])
         @test filter(mono -> degree(mono) == 0, X) == monomial_vector([x^0])
     end
+    @testset "Noncommutative div" begin
+        @ncpolyvar x y
+	err = ErrorException("Not implemented yet")
+	@test_throws err div(x, x * y)
+    end
 end