Add a small test

Author: joschmitt

test/generic/MPoly-test.jl

@@ -1877,3 +1877,20 @@ end
   R2, (x2, y2) = polynomial_ring(QQ, [:x, :y])
   @test_throws ErrorException z1 + y2
 end
+
+@testset "Generic.MPoly.Iterators" begin
+  R, (x, y, z) = polynomial_ring(QQ, [:x, :y, :z])
+  f = x * y + 2 * x - 3 * z
+
+  @test @inferred collect(exponent_vectors(f)) == [[1, 1, 0], [1, 0, 0], [0, 0, 1]]
+  @test @inferred collect(exponent_vectors(Vector{UInt}, f)) == [UInt[1, 1, 0], UInt[1, 0, 0], UInt[0, 0, 1]]
+  @test @inferred collect(coefficients(f)) == [QQ(1), QQ(2), QQ(-3)]
+  @test @inferred collect(terms(f)) == [x * y, 2 * x, -3 * z]
+  @test @inferred collect(monomials(f)) == [x * y, x, z]
+
+  @test @inferred first(exponent_vectors(f, inplace = true)) == [1, 1, 0]
+  @test @inferred first(exponent_vectors(Vector{UInt}, f, inplace = true)) == UInt[1, 1, 0]
+  @test @inferred first(coefficients(f, inplace = true)) == QQ(1)
+  @test @inferred first(monomials(f, inplace = true)) == x * y
+  @test @inferred first(terms(f, inplace = true)) == x * y
+end