   end
 
   # Tuple module
-  # We check two variants due to inlining.
+  # We check two variants of each function due to inlining.
 
-  test "duplicate" do
+  test "duplicate/2" do
     assert Tuple.duplicate(:foo, 0) == {}
     assert Tuple.duplicate(:foo, 3) == {:foo, :foo, :foo}
 

    assert mod.duplicate(:foo, 3) == {:foo, :foo, :foo}
  end

  test "insert at" do
    assert Tuple.insert_at({:bar, :baz}, 0, :foo) == {:foo, :bar, :baz}

    mod = Tuple
    assert mod.insert_at({:bar, :baz}, 0, :foo) == {:foo, :bar, :baz}
  end

  test "append" do
    assert Tuple.append({:foo, :bar}, :baz) == {:foo, :bar, :baz}

    mod = Tuple
    assert mod.append({:foo, :bar}, :baz) == {:foo, :bar, :baz}
  end

  test "delete at" do
    assert Tuple.delete_at({:foo, :bar, :baz}, 0) == {:bar, :baz}

    mod = Tuple


  doctest Tuple

  # Tuple-related functions in the Kernel module.

  test "Kernel.elem/2" do
    assert elem({:a, :b, :c}, 1) == :b
  end

  test "Kernel.put_elem/3" do
    assert put_elem({:a, :b, :c}, 1, :d) == {:a, :d, :c}
  end

  test "keyword syntax is supported in tuple literals" do
    assert {1, 2, three: :four} == {1, 2, [three: :four]}
  end

  test "optional comma is supported in tuple literals" do
    assert {1} == {1,}
    assert {1, 2, 3} == {1, 2, 3,}
  end
