Fix #128

Author: blegat

src/operators.jl

@@ -7,7 +7,7 @@ function Base.isless(t1::AbstractTerm, t2::AbstractTerm)
     if monomial(t1) < monomial(t2)
         true
     elseif monomial(t1) == monomial(t2)
-        coefficient(t1) < coefficient(t2)
+        abs(coefficient(t1)) < abs(coefficient(t2))
     else
         false
     end

test/polynomial.jl

@@ -166,4 +166,11 @@ const MP = MultivariatePolynomials
         @test T[y, z] == @inferred effective_variables(z + 0 * x + y)
         @test T[z] == @inferred effective_variables(z + 0 * x + y^0)
     end
+
+    @testset "Complex" begin
+        # See https://github.com/JuliaAlgebra/MultivariatePolynomials.jl/issues/128
+        Mod.@polyvar x
+        p = im * x + 2im * x^2
+        @test p * p == -x^2 - 4x^4 - 4x^3
+    end
 end