From 87a8b0b38607298b1f9ae1772f82173a1e0bd0e5 Mon Sep 17 00:00:00 2001
From: Yuki <yuki@stripe.com>
Date: Mon, 15 Mar 2021 16:55:56 -0700
Subject: [PATCH] Add decline code to userInfo of STPError (#112)

---
 Stripe/STPError.swift             |  8 ++++++++
 Tests/Tests/StripeErrorTest.swift | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Stripe/STPError.swift b/Stripe/STPError.swift
index 4948e0c085..bd6cc005cb 100644
--- a/Stripe/STPError.swift
+++ b/Stripe/STPError.swift
@@ -48,6 +48,10 @@ public class STPError: NSObject {
     /// The error type returned by the Stripe API.
     /// - seealso: https://stripe.com/docs/api#errors-type
     @objc public static let stripeErrorTypeKey = "com.stripe.lib:StripeErrorTypeKey"
+    /// If the value of `userInfo[stripeErrorCodeKey]` is `STPError.cardDeclined`,
+    /// the value for this key contains the decline code.
+    /// - seealso: https://stripe.com/docs/declines/codes
+    @objc public static let stripeDeclineCodeKey = "com.stripe.lib:DeclineCodeKey"
 
     /// The card number is not a valid credit card number.
     @objc public static let invalidNumber = STPCardErrorCode.invalidNumber.rawValue
@@ -186,6 +190,10 @@ public enum STPCardErrorCode: String {
             let cardErrorCode = codeMapEntry?["code"]
             let localizedMessage = codeMapEntry?["message"]
             if let cardErrorCode = cardErrorCode {
+                if cardErrorCode == STPCardErrorCode.cardDeclined.rawValue,
+                   let decline_code = errorDictionary["decline_code"] {
+                    userInfo[STPError.stripeDeclineCodeKey] = decline_code
+                }
                 userInfo[STPError.cardErrorCodeKey] = cardErrorCode
             }
             if localizedMessage != nil {
diff --git a/Tests/Tests/StripeErrorTest.swift b/Tests/Tests/StripeErrorTest.swift
index 1b07861a9b..35c0988110 100644
--- a/Tests/Tests/StripeErrorTest.swift
+++ b/Tests/Tests/StripeErrorTest.swift
@@ -123,4 +123,24 @@ class StripeErrorTest: XCTestCase {
         XCTAssertEqual(
             error.userInfo[STPError.errorMessageKey] as? String, response["error"]!["message"])
     }
+
+    func testCardDeclinedError() {
+        let response = [
+            "error": [
+                "type": "card_error",
+                "message": "Your card has insufficient funds.",
+                "code": "card_declined",
+                "decline_code": "insufficient_funds",
+            ]
+        ]
+        guard let error = NSError.stp_error(fromStripeResponse: response) else {
+            XCTFail()
+            return
+        }
+        XCTAssertEqual(error.domain, STPError.stripeDomain)
+        XCTAssertEqual(error.code, STPErrorCode.cardError.rawValue)
+        XCTAssertEqual(error.userInfo[STPError.cardErrorCodeKey] as? String, STPCardErrorCode.cardDeclined.rawValue)
+        XCTAssertEqual(error.userInfo[NSLocalizedDescriptionKey] as? String, NSError.stp_cardErrorDeclinedUserMessage())
+        XCTAssertEqual(error.userInfo[STPError.stripeDeclineCodeKey] as? String, "insufficient_funds")
+    }
 }