From 71ca7626e28125f073cee0474aa96564162211c0 Mon Sep 17 00:00:00 2001
From: Josh Rotenberg <joshrotenberg@gmail.com>
Date: Fri, 15 May 2026 11:45:45 -0700
Subject: [PATCH] fix(account): PaymentMethod.credit_card_ends_with should be
 String, not i32
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The OpenAPI example for `PaymentMethod` shows `creditCardEndsWith` as a
string, and real responses commonly include leading-zero card tails
(e.g. `"0042"`) that lose information when typed as `i32` — or fail to
deserialize entirely if the value contains non-numeric formatting.

Strengthens `test_get_account_payment_methods` from a vacuous
`account_id.is_some()` check to a realistic round-trip that includes a
`paymentMethods` array with a leading-zero card tail and asserts the
field comes through intact.

Breaking change to a public field type. The previous typing would
silently mis-handle real responses, so no production caller can have
been relying on the numeric form.

Refs #40 (spec deltas tracking)
Closes #77
---
 src/account.rs         |  8 ++++++--
 tests/account_tests.rs | 26 ++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/account.rs b/src/account.rs
index 2363a16..bc9fd0c 100644
--- a/src/account.rs
+++ b/src/account.rs
@@ -239,9 +239,13 @@ pub struct PaymentMethod {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub r#type: Option<String>,
 
-    /// Last 4 digits of the credit card
+    /// Last digits of the credit card as a masked string.
+    ///
+    /// Typed as `Option<String>` because the OpenAPI example shows a string
+    /// value and real responses can include leading zeros (`"0042"`) or
+    /// non-numeric formatting that would be lost or fail to parse as `i32`.
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub credit_card_ends_with: Option<i32>,
+    pub credit_card_ends_with: Option<String>,
 
     /// Name on the card
     #[serde(skip_serializing_if = "Option::is_none")]
diff --git a/tests/account_tests.rs b/tests/account_tests.rs
index 5b0ebb0..3f0c7cc 100644
--- a/tests/account_tests.rs
+++ b/tests/account_tests.rs
@@ -182,12 +182,26 @@ async fn test_get_supported_regions() {
 async fn test_get_account_payment_methods() {
     let mock_server = MockServer::start().await;
 
+    // Realistic shape including a paymentMethods array entry with a
+    // string `creditCardEndsWith` containing leading zeros — the previous
+    // `Option<i32>` typing would either drop the leading zero or fail
+    // outright.
     Mock::given(method("GET"))
         .and(path("/payment-methods"))
         .and(header("x-api-key", "test-key"))
         .and(header("x-api-secret-key", "test-secret"))
         .respond_with(ResponseTemplate::new(200).set_body_json(json!({
-            "accountId": 123
+            "accountId": 123,
+            "paymentMethods": [
+                {
+                    "id": 555,
+                    "type": "Visa",
+                    "creditCardEndsWith": "0042",
+                    "nameOnCard": "Alex Example",
+                    "expirationMonth": 9,
+                    "expirationYear": 2030
+                }
+            ]
         })))
         .mount(&mock_server)
         .await;
@@ -202,7 +216,15 @@ async fn test_get_account_payment_methods() {
     let handler = AccountHandler::new(client);
     let result = handler.get_account_payment_methods().await.unwrap();
 
-    assert!(result.account_id.is_some());
+    assert_eq!(result.account_id, Some(123));
+    let methods = result
+        .payment_methods
+        .expect("response should include paymentMethods");
+    assert_eq!(methods.len(), 1);
+    assert_eq!(methods[0].id, Some(555));
+    assert_eq!(methods[0].r#type.as_deref(), Some("Visa"));
+    // Regression guard for #77: leading-zero card tails survive the round-trip.
+    assert_eq!(methods[0].credit_card_ends_with.as_deref(), Some("0042"));
 }
 
 #[tokio::test]