From f2594d83ddc408d41d17c56e28221467047ca796 Mon Sep 17 00:00:00 2001
From: Lance Ball <lball@redhat.com>
Date: Mon, 6 Mar 2017 17:15:59 -0500
Subject: [PATCH] fix: circuit should emit failure event on fallback

Fixes: https://github.com/bucharest-gold/opossum/issues/28
---
 lib/circuit.js | 12 ++++++------
 test/test.js   | 16 +++++++++++++++-
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/lib/circuit.js b/lib/circuit.js
index 26a1e7f7..5a45f8d4 100644
--- a/lib/circuit.js
+++ b/lib/circuit.js
@@ -178,8 +178,8 @@ class CircuitBreaker extends EventEmitter {
        * @event CircuitBreaker#reject
        */
       this.emit('reject', new Error('Breaker is open'));
-      return fallback(this, 'Breaker is open', args) ||
-             fail(this, 'Breaker is open', args);
+      const failure = fail(this, 'Breaker is open', args);
+      return fallback(this, 'Breaker is open', args) || failure;
     }
     this[PENDING_CLOSE] = this.halfOpen;
 
@@ -218,15 +218,16 @@ class CircuitBreaker extends EventEmitter {
           })
           .catch((error) => {
             clearTimeout(timeout);
+            fail(this, error, args);
             const fb = fallback(this, error, args);
             if (fb) return resolve(fb);
-            fail(this, error, args);
-            reject(error);
+            else reject(error);
           });
       });
     } catch (error) {
       clearTimeout(timeout);
-      return fallback(this, error, args) || fail(this, error, args);
+      fail(this, error, args);
+      return fallback(this, error, args);
     }
   }
 }
@@ -257,7 +258,6 @@ function fail (circuit, err, args) {
   if (circuit[NUM_FAILURES] >= circuit.options.maxFailures) {
     circuit.open();
   }
-
   return circuit.Promise.reject.apply(null, [err]);
 }
 
diff --git a/test/test.js b/test/test.js
index 4c6a259e..5738c354 100644
--- a/test/test.js
+++ b/test/test.js
@@ -201,6 +201,19 @@ test('Returns self from fallback()', (t) => {
     .catch(t.fail);
 });
 
+test('CircuitBreaker emits failure when falling back', (t) => {
+  t.plan(2);
+  const breaker = cb(passFail).fallback(() => 'fallback value');
+
+  breaker.on('failure', (err) => {
+    t.equals(err, 'Error: -1 is < 0', 'Unexpected error');
+  });
+
+  breaker.fire(-1).then((result) => {
+    t.equals('fallback value', result, 'fallback value is correct');
+  }).catch(t.fail);
+});
+
 test('CircuitBreaker status', (t) => {
   t.plan(11);
   const breaker = cb(passFail, { maxFailures: 1 });
@@ -226,12 +239,13 @@ test('CircuitBreaker status', (t) => {
           breaker.fire(-20)
             .then((result) => {
               t.equal(result, 'Fallback called', 'fallback is invoked');
-              t.equal(breaker.status.failures, 1, 'status reports 1 failures');
+              t.equal(breaker.status.failures, 2, 'status reports 2 failures');
               t.equal(breaker.status.fires, 5, 'status reports 5 fires');
               t.equal(breaker.status.fallbacks, 1, 'status reports 1 fallback');
             })
             .catch(t.fail);
         })
+        .catch(t.fail)
         .then(t.end);
     });
 });