Add tests for mutability of output of zero/one

Author: blegat

Project.toml

@@ -11,7 +11,7 @@ MutableArithmetics = "d8a4904e-b15c-11e9-3269-09a3773c0cb0"
 
 [compat]
 DataStructures = "0.17.7"
-DynamicPolynomials = "0.3.11"
+DynamicPolynomials = "0.3.12"
 MutableArithmetics = "0.2"
 TypedPolynomials = "0.2.8"
 julia = "1"

test/division.jl

@@ -69,6 +69,12 @@ const MP = MultivariatePolynomials
         @test q == [x, 0]
         @test r == 0
 
+        @testset "Issue DynamicPolynomials#62" begin
+            p = x^2 + x + 1
+            q = rem(p, [x^2-y])
+            @test q == x + y + 1
+        end
+
         @test (@inferred rem(x^2*y + (1+1e-10)*x*y + 1, [x^2 + x, y + 1])) == 1
         @test (@inferred rem(x^2*y + (1+1e-10)*x*y + 1, [x^2 + x, y + 1]; ztol=1e-11)) == -((1+1e-10)-1)x + 1
     end

test/polynomial.jl

@@ -173,4 +173,11 @@ const MP = MultivariatePolynomials
         p = im * x + 2im * x^2
         @test p * p == -x^2 - 4x^4 - 4x^3
     end
+
+    @testset "$f is a mutable copy, see issue DynamicPolynomials#62" for f in [zero, one]
+        p = 2x + 1
+        q = f(p)
+        q = MA.add!(q, 2y)
+        @test p == 2x + 1
+    end
 end