Deprecate order, use degree (#461)

* Deprecate `order`, use `degree`

as in #457

* Add test for `order`

Author: singularitti

src/common.jl

@@ -6,7 +6,6 @@ export fromroots,
        coeffs,
        degree,
        mapdomain,
-       order,
        hasnan,
        roots,
        companion,
@@ -586,6 +585,7 @@ has a nonzero coefficient. The degree of the zero polynomial is defined to be -1
 """
 degree(p::AbstractPolynomial) = iszero(coeffs(p)) ? -1 : length(coeffs(p)) - 1 + min(0, minimumexponent(p))
 
+@deprecate order degree true
 
 """
     Polynomials.domain(::Type{<:AbstractPolynomial})

test/ChebyshevT.jl

@@ -10,6 +10,7 @@
         @test p.coeffs == coeff
         @test coeffs(p) == coeff
         @test degree(p) == length(coeff) - 1
+        @test (@test_deprecated order(p)) == length(coeff) - 1
         @test Polynomials.indeterminate(p) == :x
         @test length(p) == length(coeff)
         @test size(p) == size(coeff)