add a test for macro hygiene when using import

Author: rdeits

test/mono.jl

@@ -15,3 +15,14 @@ facts("Vector to Monomial Vector") do
     @fact MonomialVector([1]) --> MonomialVector(PolyVar[], [Int[]])
     @fact MonomialVector([x]) --> MonomialVector([x], [[1]])
 end
+module newmodule
+  using FactCheck
+  import MultivariatePolynomials
+  facts("Polyvar macro hygiene") do
+    # Verify that the @polyvar macro works when the package has been activated
+    # with `import` instead of `using`.
+    MultivariatePolynomials.@polyvar x y
+    @fact isa(x, MultivariatePolynomials.PolyVar) --> true
+    @fact isa(y, MultivariatePolynomials.PolyVar) --> true
+  end
+end