Merge pull request #17 from fremantle-capital/struct-insufficient-bal…

…ance-error

Return struct for insufficient balance error

fixture/vcr_cassettes/order_limit_buy_error_insufficient_balance.json

@@ -0,0 +1,40 @@
+[
+  {
+    "request": {
+      "body": "price=0.001&quantity=10000&recvWindow=1000&side=BUY&symbol=LTCBTC&timeInForce=FOK&timestamp=1528091845716&type=LIMIT&signature=***",
+      "headers": {
+        "X-MBX-APIKEY": "***"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://api.binance.com/api/v3/order"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"code\":-2010,\"msg\":\"Account has insufficient balance for requested action.\"}",
+      "headers": {
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Date": "Mon, 04 Jun 2018 05:57:25 GMT",
+        "Server": "nginx",
+        "Strict-Transport-Security": "max-age=31536000; includeSubdomains",
+        "X-Frame-Options": "SAMEORIGIN",
+        "X-Xss-Protection": "1; mode=block",
+        "X-Content-Type-Options": "nosniff",
+        "Content-Security-Policy": "default-src 'self'",
+        "X-Content-Security-Policy": "default-src 'self'",
+        "X-WebKit-CSP": "default-src 'self'",
+        "Cache-Control": "no-cache, no-store, must-revalidate",
+        "Pragma": "no-cache",
+        "Expires": "0",
+        "X-Cache": "Error from cloudfront",
+        "Via": "1.1 a8a06e035420932f2808c2efee52f455.cloudfront.net (CloudFront)",
+        "X-Amz-Cf-Id": "UF3P5hkV9dU_7OiQrz4RkgvAwZhaJy0AyTZDasjdwOyz0ax44Lhbdw=="
+      },
+      "status_code": 400,
+      "type": "ok"
+    }
+  }
+]

lib/binance.ex

@@ -420,6 +420,16 @@ defmodule Binance do
     {:ok, Binance.OrderResponse.new(response)}
   end
 
+  defp parse_order_response({
+         :error,
+         {
+           :binance_error,
+           %{code: -2010, msg: "Account has insufficient balance for requested action."} = reason
+         }
+       }) do
+    {:error, %Binance.InsufficientBalanceError{reason: reason}}
+  end
+
   # Misc
 
   @doc """

lib/binance/insufficient_balance_error.ex

@@ -0,0 +1,4 @@
+defmodule Binance.InsufficientBalanceError do
+  @enforce_keys [:reason]
+  defstruct [:reason]
+end

test/binance_test.exs

@@ -145,6 +145,19 @@ defmodule BinanceTest do
         assert response.type == "LIMIT"
       end
     end
+
+    test "returns an insufficient balance error tuple" do
+      use_cassette "order_limit_buy_error_insufficient_balance" do
+        assert {:error, reason} = Binance.order_limit_buy("LTCBTC", 10_000, 0.001, "FOK")
+
+        assert reason == %Binance.InsufficientBalanceError{
+                 reason: %{
+                   code: -2010,
+                   msg: "Account has insufficient balance for requested action."
+                 }
+               }
+      end
+    end
   end
 
   describe ".order_limit_sell" do