Resolve unhandled rejection in BeforeFeatures hook #797

features/hooks.feature

@@ -253,6 +253,39 @@ Feature: Environment Hooks
       ]
       """
 
+  Scenario: Failing the BeforeFeatures hook exists immediately with code = 1
+    Given a file named "features/a.feature" with:
+      """
+      Feature: some feature
+
+      Scenario: I've declared one step and it is passing
+          Given This step is passing
+      """
+    And a file named "features/step_definitions/cucumber_steps.js" with:
+      """
+      var cucumberSteps = function() {
+        this.Given(/^This step is passing$/, function(callback) { callback(); });
+      };
+      module.exports = cucumberSteps;
+      """
+    And a file named "features/support/hooks.js" with:
+      """
+      var hooks = function () {
+        this.registerHandler('BeforeFeatures', function(){
+            return Promise.reject(new Error('Something bad'));
+        });
+      };
+
+      module.exports = hooks;
+      """
+    When I run cucumber.js with `-f json`
+    Then the exit status should be 1
+    And the error output contains the text: 
+    """
+      features/support/hooks.js:2 Something bad
+    """
+    And it does not output a valid JSON
+
   Scenario: Hooks still execute after a failure
     Given a file named "features/a.feature" with:
       """

features/step_definitions/json_output_steps.js

@@ -203,6 +203,19 @@ var jsonOutputSteps = function jsonOutputSteps() {
     var features = JSON.parse(this.lastRun.stdout);
     assert.equal(features[0].elements[0].description.trim(), description);
   });
+
+  this.Then(/^it (does not)? ?outputs? a valid JSON$/, function(expected){
+    var expectedValid = (expected != 'does not');
+    var isValid = true;
+    try {
+        JSON.parse(this.lastRun.stdout);
+    } catch (e) {
+      isValid = false;
+    }
+
+
+    assert.equal(expectedValid, isValid);
+  });
 
 };
 

lib/cucumber/runtime/event_broadcaster.js

@@ -27,7 +27,7 @@ function EventBroadcaster(listeners, listenerDefaultTimeout) {
       Cucumber.Util.asyncForEach(listeners, function (listener, callback) {
         listener.hear(event, listenerDefaultTimeout, function(error) {
           if (error) {
-            throw error;
+            process.nextTick(function(){ throw error; }); // prevent swallow by unhandled rejection
           }
           callback();
         });