Throwing error if nxo response is null (#682)

* -Throwing error if response is null

* -Updating changelog

* -Adding in exception

* -Adding test

* Update CHANGELOG.md

Co-authored-by: Jax DesMarais-Leder <[email protected]>

---------

Co-authored-by: Jax DesMarais-Leder <[email protected]>

CHANGELOG.md

@@ -1,6 +1,9 @@
 # Braintree Android SDK Release Notes
 
 ## unreleased
+* PayPalNativeCheckout (BETA)
+
+  * Fixes a bug where an error was not thrown inside `PayPalNativeCheckoutClient` when no PayPal response was received from the API
 
 * SharedUtils
   * Replace EncryptedSharedPreferences with SharedPreferences for internal persistent data storage for all payment flows

PayPalNativeCheckout/src/main/java/com/braintreepayments/api/PayPalNativeCheckoutClient.java

@@ -203,6 +203,8 @@ private void sendPayPalRequest(
                         braintreeClient.sendAnalyticsEvent("paypal-native.billing-agreement.succeeded");
                     }
                 });
+            } else {
+                listener.onPayPalFailure(new Exception(error));
             }
         });
     }

PayPalNativeCheckout/src/test/java/com/braintreepayments/api/PayPalNativeCheckoutClientUnitTest.java

@@ -128,6 +128,27 @@ public void requestBillingAgreement_launchNativeCheckout_sendsAnalyticsEvents()
         verify(braintreeClient).sendAnalyticsEvent("paypal-native.billing-agreement.started");
     }
 
+    @Test
+    public void requestNativeCheckout_returnsErrorFromFailedResponse() {
+        PayPalNativeCheckoutVaultRequest payPalVaultRequest = new PayPalNativeCheckoutVaultRequest();
+        payPalVaultRequest.setMerchantAccountId("sample-merchant-account-id");
+        payPalVaultRequest.setReturnUrl("returnUrl://paypalpay");
+
+        PayPalNativeCheckoutInternalClient payPalInternalClient = new MockPayPalInternalClientBuilder()
+                .sendRequestError(new Exception())
+                .build();
+
+        BraintreeClient braintreeClient = new MockBraintreeClientBuilder()
+                .configuration(payPalEnabledConfig)
+                .build();
+
+        PayPalNativeCheckoutClient sut = new PayPalNativeCheckoutClient(braintreeClient, payPalInternalClient);
+        sut.setListener(listener);
+        sut.launchNativeCheckout(activity, payPalVaultRequest);
+
+        verify(listener).onPayPalFailure(any());
+    }
+
     @Test
     public void requestOneTimePayment_launchNativeCheckout_sendsAnalyticsEvents() {
         PayPalNativeCheckoutRequest payPalCheckoutRequest = new PayPalNativeCheckoutRequest("1.00");