Merge pull request recurly#417 from recurly/fix-checkout-coupon-curre…

…ncy-safety

Fix checkout coupon currency safety

lib/recurly/pricing/checkout/calculations.js

@@ -384,8 +384,10 @@ export default class Calculations {
         discountNext = roundForDiscount(discountableNext * coupon.discount.rate);
       } else if (coupon.discount.amount) {
         const { discountableNow, discountableNext } = this.discountableSubtotals(coupon);
-        discountNow = Math.min(discountableNow, coupon.discount.amount[this.items.currency]);
-        discountNext = Math.min(discountableNext, coupon.discount.amount[this.items.currency]);
+        // Falls back to zero if the coupon does not support the checkout currency
+        const discountAmount = coupon.discount.amount[this.items.currency] || 0;
+        discountNow = Math.min(discountableNow, discountAmount);
+        discountNext = Math.min(discountableNext, discountAmount);
       }
     }
     return { discountNow, discountNext };

lib/recurly/pricing/checkout/index.js

@@ -259,27 +259,29 @@ export default class CheckoutPricing extends Pricing {
       this.emit('unset.coupon');
     };
 
-    return new PricingPromise((resolve, reject) => {
-      if (this.items.coupon) this.remove({ coupon: this.items.coupon.code });
-
-      // A blank coupon is handled as ok
-      if (!couponCode) {
-        unset();
-        return resolve();
-      }
-
-      this.recurly.coupon({ plans: this.subscriptionPlanCodes, coupon: couponCode }, (err, coupon) => {
-        if (err && err.code === 'not-found') unset();
-        if (err) {
-          return this.error(err, reject, 'coupon');
-        } else {
-          debug('set.coupon');
-          this.items.coupon = coupon;
-          this.emit('set.coupon', coupon);
-          resolve(coupon);
+    return new PricingPromise(resolve => resolve(), this)
+      .then(() => {
+        if (this.items.coupon) return this.remove({ coupon: this.items.coupon.code });
+      })
+      .then(() => new PricingPromise((resolve, reject) => {
+        // A blank coupon is handled as ok
+        if (!couponCode) {
+          unset();
+          return resolve();
         }
-      });
-    }, this);
+
+        this.recurly.coupon({ plans: this.subscriptionPlanCodes, coupon: couponCode }, (err, coupon) => {
+          if (err && err.code === 'not-found') unset();
+          if (err) {
+            return this.error(err, reject, 'coupon');
+          } else {
+            debug('set.coupon');
+            this.items.coupon = coupon;
+            this.emit('set.coupon', coupon);
+            resolve(coupon);
+          }
+        });
+      }));
   }
 
   /**
@@ -377,9 +379,9 @@ export default class CheckoutPricing extends Pricing {
         if (options.coupon) {
           // Remove the coupon from embedded subscriptions
           Promise.all(this.validSubscriptions.map(sub => sub.coupon().reprice({ internal: true })))
-            .then(() => resolve(super.remove(options)));
+            .then(() => super.remove(options).then(resolve, reject));
         } else {
-          resolve(super.remove(options));
+          super.remove(options).then(resolve, reject);
         }
       }
     });

lib/recurly/pricing/index.js

@@ -115,6 +115,7 @@ export class Pricing extends Emitter {
           reason: 'does not exist on this pricing instance.'
         }), reject);
       }
+      resolve();
     }, this).nodeify(done);
   }
 

test/pricing/checkout/checkout.test.js

@@ -516,7 +516,24 @@ describe('CheckoutPricing', function () {
           assert.equal(coupon.code, valid);
           done();
         });
-        this.pricing.coupon('coop').done();
+        this.pricing.coupon(valid).done();
+      });
+    });
+
+    describe('when given a valid coupon code that does not support the checkout currency', () => {
+      const incompatible = 'coop-fixed-all-500-eur';
+      it('does not discount the checkout', function (done) {
+        this.pricing
+          .coupon(incompatible)
+          .done(price => {
+            assert.equal(this.pricing.items.coupon.code, incompatible);
+            assert.equal(this.pricing.items.currency, 'USD');
+            assert.equal('USD' in this.pricing.items.coupon.discount.amount, false);
+            assert.equal('EUR' in this.pricing.items.coupon.discount.amount, true);
+            assert.equal(price.now.discount, 0);
+            assert.equal(price.next.discount, 0);
+            done();
+          });
       });
     });
 
@@ -527,12 +544,18 @@ describe('CheckoutPricing', function () {
 
       it(`accepts a blank coupon code and unsets the existing coupon,
           firing the unset.coupon event`, function (done) {
+        const part = after(2, done);
+        const errorSpy = sinon.spy();
         assert.equal(this.pricing.items.coupon.code, 'coop');
         this.pricing.on('unset.coupon', () => {
           assert.equal(this.pricing.items.coupon, undefined);
-          done();
+          part();
+        });
+        this.pricing.on('error', errorSpy);
+        this.pricing.coupon().done(price => {
+          assert.equal(errorSpy.callCount, 0);
+          part();
         });
-        this.pricing.coupon().done();
       });
     });
 

test/server/fixtures/coupons/coop-fixed-all-500-eur.json

@@ -0,0 +1,16 @@
+{
+  "code": "coop-fixed-all-500-eur",
+  "name": "Test coupon: EUR 500 off all charges",
+  "discount": {
+    "type": "dollars",
+    "amount": {
+      "EUR": 500
+    }
+  },
+  "plans": [],
+  "single_use": false,
+  "applies_to_non_plan_charges": true,
+  "applies_to_plans": true,
+  "applies_to_all_plans": true,
+  "redemption_resource": "account"
+}