Add balance transactions and endpoints

lib/stripe/core_resources/balance.ex

@@ -49,4 +49,45 @@ defmodule Stripe.Balance do
     |> put_method(:get)
     |> make_request()
   end
+
+  @doc """
+  Retrieves a balance transaction
+
+  See the [Stripe docs](https://stripe.com/docs/api#balance_transaction_retrieve).
+  """
+  @spec retrieve_transaction(String.t(), Stripe.options()) :: {:ok, t} | {:error, Stripe.Error.t()}
+  def retrieve_transaction(id, opts \\ []) do
+    new_request(opts)
+    |> put_endpoint(@endpoint <> "/history/" <> id)
+    |> put_method(:get)
+    |> make_request()
+  end
+
+  @doc """
+  List balance history
+
+  See the [Stripe docs](https://stripe.com/docs/api#balance_history).
+  """
+  @spec list(params, Stripe.options()) :: {:ok, Stripe.List.t(t)} | {:error, Stripe.Error.t()}
+        when params: %{
+               optional(:available_on) => Stripe.date_query(),
+               optional(:created) => Stripe.date_query(),
+               optional(:currency) => String.t(),
+               optional(:ending_before) => t | Stripe.id(),
+               optional(:limit) => 1..100,
+               optional(:payout) => String.t(),
+               optional(:source) => %{
+                 optional(:object) => String.t()
+               },
+               optional(:starting_after) => t | Stripe.id(),
+               optional(:type) => String.t()
+             }
+  def list(params \\ %{}, opts \\ []) do
+    new_request(opts)
+    |> put_endpoint(@endpoint <> "/history")
+    |> put_method(:get)
+    |> put_params(params)
+    |> cast_to_id([:available_on, :created, :ending_before, :starting_after])
+    |> make_request()
+  end
 end

lib/stripe/core_resources/balance_transaction.ex

@@ -18,10 +18,10 @@ defmodule Stripe.BalanceTransaction do
           created: Stripe.timestamp(),
           currency: String.t(),
           description: String.t() | nil,
+          exchange_rate: integer | nil,
           fee: integer,
           fee_details: list(Stripe.Types.fee()) | [],
           net: integer,
-          # TODO: clarify these
           source: Stripe.id() | Stripe.Source.t() | nil,
           status: String.t(),
           type: String.t()
@@ -35,6 +35,7 @@ defmodule Stripe.BalanceTransaction do
     :created,
     :currency,
     :description,
+    :exchange_rate,
     :fee,
     :fee_details,
     :net,

test/stripe/core_resources/balance_test.exs

@@ -1,6 +1,18 @@
 defmodule Stripe.BalanceTest do
   use Stripe.StripeCase, async: true
 
+  test "is listable" do
+    assert {:ok, %Stripe.List{data: balances}} = Stripe.Balance.list()
+    assert_stripe_requested(:get, "/v1/balance/history")
+    assert is_list(balances)
+    assert %Stripe.BalanceTransaction{} = hd(balances)
+  end
+
+  test "transaction is retrievable" do
+    assert {:ok, %Stripe.BalanceTransaction{}} = Stripe.Balance.retrieve_transaction("b_123")
+    assert_stripe_requested(:get, "/v1/balance/history/#{"b_123"}")
+  end
+
   test "is retrievable" do
     assert {:ok, %Stripe.Balance{}} = Stripe.Balance.retrieve()
     assert_stripe_requested(:get, "/v1/balance")