test(membership-fees): share create_fee_type and create_cycle fixtures

Replace the create_fee_type/create_cycle helpers duplicated across 18/8
membership-fee test files with a single shared definition in Mv.Fixtures,
reconciling the divergent local signatures (including the reversed
argument order) into one superset so behavior is unchanged.

test/support/fixtures.ex

@@ -335,4 +335,82 @@ defmodule Mv.Fixtures do
     {:ok, request} = Membership.confirm_join_request(token, actor: nil)
     request
   end
+
+  @doc """
+  Creates a membership fee type with default or custom attributes.
+
+  Defaults: a unique `name`, `amount` 50.00, `interval` :yearly.
+
+  ## Parameters
+    - `attrs` - Map of attributes to override defaults (e.g. `%{interval: :monthly}`).
+    - `actor` - the authorization actor; defaults to the system actor when omitted/nil.
+
+  ## Returns
+    - MembershipFeeType struct.
+
+  ## Examples
+
+      iex> create_fee_type(%{interval: :monthly})
+      %Mv.MembershipFees.MembershipFeeType{interval: :monthly, ...}
+
+      iex> create_fee_type(%{amount: Decimal.new("10.00")}, admin)
+      %Mv.MembershipFees.MembershipFeeType{...}
+  """
+  def create_fee_type(attrs \\ %{}, actor \\ nil) do
+    actor = actor || SystemActor.get_system_actor()
+
+    default_attrs = %{
+      name: "Test Fee Type #{System.unique_integer([:positive])}",
+      amount: Decimal.new("50.00"),
+      interval: :yearly
+    }
+
+    Mv.MembershipFees.MembershipFeeType
+    |> Ash.Changeset.for_create(:create, Map.merge(default_attrs, attrs))
+    |> Ash.create!(actor: actor)
+  end
+
+  @doc """
+  Creates a membership fee cycle for the given member and fee type.
+
+  Defaults: `cycle_start` ~D[2024-01-01], `amount` 50.00, `status` :unpaid,
+  with `member_id`/`membership_fee_type_id` derived from the passed structs.
+
+  ## Parameters
+    - `member` - the Member struct the cycle belongs to.
+    - `fee_type` - the MembershipFeeType struct the cycle references.
+    - `attrs` - Map overriding the cycle defaults (e.g. `%{cycle_start: ~D[2023-01-01], status: :paid}`).
+      A reserved `:replace_existing` key (truthy) deletes any pre-existing cycles for the member
+      before creating the new one (used where auto-generated cycles would otherwise conflict);
+      it is stripped from the attrs and never passed to the create action. Defaults to absent/false.
+    - `actor` - the authorization actor; defaults to the system actor when omitted/nil.
+
+  ## Returns
+    - MembershipFeeCycle struct.
+  """
+  def create_cycle(member, fee_type, attrs \\ %{}, actor \\ nil) do
+    actor = actor || SystemActor.get_system_actor()
+    {replace_existing, attrs} = Map.pop(attrs, :replace_existing, false)
+
+    if replace_existing do
+      require Ash.Query
+
+      Mv.MembershipFees.MembershipFeeCycle
+      |> Ash.Query.filter(member_id == ^member.id)
+      |> Ash.read!(actor: actor)
+      |> Enum.each(&Ash.destroy!(&1, actor: actor))
+    end
+
+    default_attrs = %{
+      cycle_start: ~D[2024-01-01],
+      amount: Decimal.new("50.00"),
+      member_id: member.id,
+      membership_fee_type_id: fee_type.id,
+      status: :unpaid
+    }
+
+    Mv.MembershipFees.MembershipFeeCycle
+    |> Ash.Changeset.for_create(:create, Map.merge(default_attrs, attrs))
+    |> Ash.create!(actor: actor)
+  end
 end