fix: Correct decision notification payload type for getVariation feature test decision (#375)

Summary:

In createProjectConfig, we attempt to create an object experimentFeatureMap whose keys are experiment IDs, and whose values are arrays of feature IDs. We loop over each experiment ID in each feature flag's experimentIds, and update experimentFeatureMap accordingly. The problem occurs when one of these experiments is in a group (had a groupId property). The inner loop breaks out by returning false (this early iteration exit by returning false is a feature of lodash forEach). Then, any remaining experiment IDs are wrongfully excluded from experimentFeatureMap. For any of these skipped feature experiment IDs, the isFeatureExperiment function will wrongly return false, leading to an incorrect decision notification payload. With this change, the loop always runs over all experiment IDs of each feature. The previous behavior of only assigning feature.groupId once is maintained.

Test plan:
New unit tests for isFeatureExperiment function of project config module

Issues:
https://optimizely.atlassian.net/browse/OASIS-5759

Author: mjc1283

packages/optimizely-sdk/lib/core/project_config/index.js

@@ -98,16 +98,15 @@ module.exports = {
       fns.forEach(feature.experimentIds || [], function(experimentId) {
         // Add this experiment in experiment-feature map.
         if (projectConfig.experimentFeatureMap[experimentId]) {
-          projectConfig.experimentFeatureMap[experimentId].push(feature.id);  
+          projectConfig.experimentFeatureMap[experimentId].push(feature.id);
         } else {
           projectConfig.experimentFeatureMap[experimentId] = [feature.id];
         }
-        
+
         var experimentInFeature = projectConfig.experimentIdMap[experimentId];
-        if (experimentInFeature.groupId) {
+        // Experiments in feature can only belong to one mutex group.
+        if (experimentInFeature.groupId && !feature.groupId) {
           feature.groupId = experimentInFeature.groupId;
-          // Experiments in feature can only belong to one mutex group.
-          return false;
         }
       });
     });

packages/optimizely-sdk/lib/core/project_config/index.tests.js

@@ -559,6 +559,28 @@ describe('lib/core/project_config', function() {
         assert.deepEqual(result, ['and', ['or', '3468206642', '3988293898'], ['or', '3988293899', '3468206646', '3468206647', '3468206644', '3468206643']]);
       });
     });
+
+    describe('#isFeatureExperiment', function() {
+      it('returns true for a feature test', function() {
+        var config = projectConfig.createProjectConfig(testDatafile.getTestProjectConfigWithFeatures());
+        var result = projectConfig.isFeatureExperiment(config, '594098'); // id of 'testing_my_feature'
+        assert.isTrue(result);
+      });
+
+      it('returns false for an A/B test', function() {
+        var config = projectConfig.createProjectConfig(testDatafile.getTestProjectConfig());
+        var result = projectConfig.isFeatureExperiment(config, '111127'); // id of 'testExperiment'
+        assert.isFalse(result);
+      });
+
+      it('returns true for a feature test in a mutex group', function() {
+        var config = projectConfig.createProjectConfig(testDatafile.getMutexFeatureTestsConfig());
+        var result = projectConfig.isFeatureExperiment(config, '17128410791'); // id of 'f_test1'
+        assert.isTrue(result);
+        result = projectConfig.isFeatureExperiment(config, '17139931304'); // id of 'f_test2'
+        assert.isTrue(result);
+      });
+    });
   });
 
   describe('#tryCreatingProjectConfig', function() {

packages/optimizely-sdk/lib/tests/test_data.js

@@ -2489,6 +2489,95 @@ var typedAudiencesById = {
   },
 };
 
+var mutexFeatureTestsConfig = {
+  version: '4',
+  rollouts: [
+    {
+      experiments: [
+        {
+          status: 'Not started',
+          audienceIds: [],
+          variations: [{ variables: [], id: '17138530965', key: '17138530965', featureEnabled: false }],
+          id: '17138130490',
+          key: '17138130490',
+          layerId: '17151011617',
+          trafficAllocation: [{ entityId: '17138530965', endOfRange: 0 }],
+          forcedVariations: {},
+        }
+      ],
+      id: '17151011617',
+    }
+  ],
+  typedAudiences: [],
+  anonymizeIP: false,
+  projectId: '1715448053799999',
+  variables: [],
+  featureFlags: [
+    {
+      experimentIds: ['17128410791', '17139931304'],
+      rolloutId: '17151011617',
+      variables: [],
+      id: '17146211047',
+      key: 'f',
+    },
+  ],
+  experiments: [],
+  audiences: [],
+  groups: [
+    {
+      policy: 'random',
+      trafficAllocation: [
+        { entityId: '17139931304', endOfRange: 9900 },
+        { entityId: '17128410791', endOfRange: 10000 }
+      ],
+      experiments: [
+        {
+          status: 'Running',
+          audienceIds: [],
+          variations: [
+            { variables: [], id: 17155031309, key: 'variation_1', featureEnabled: false },
+            { variables: [], id: 17124610952, key: 'variation_2', featureEnabled: true }
+          ],
+          id: '17139931304',
+          key: 'f_test2',
+          layerId: '17149391594',
+          trafficAllocation: [
+            { entityId: '17155031309', endOfRange: 5000 },
+            { entityId: '17124610952', endOfRange: 10000 }
+          ],
+          forcedVariations: {}
+        },
+        {
+          status: 'Running',
+          audienceIds: [],
+          variations: [
+            { variables: [], id: '17175820099', key: 'variation_1', featureEnabled: false },
+            { variables: [], id: '17144050391', key: 'variation_2', featureEnabled: true }
+          ],
+          id: '17128410791',
+          key: 'f_test1',
+          layerId: '17145581153',
+          trafficAllocation: [
+            { entityId: '17175820099', endOfRange: 5000 },
+            { entityId: '17144050391', endOfRange: 10000 }
+          ],
+          forcedVariations: {}
+        }
+      ],
+      id: '17142090293'
+    }
+  ],
+  attributes: [],
+  botFiltering: false,
+  accountId: '4879520872999',
+  events: [{ experimentIds: ['17128410791', '17139931304'], id: '17140380990', key: 'e' }],
+  revision: '12',
+};
+
+var getMutexFeatureTestsConfig = function() {
+  return cloneDeep(mutexFeatureTestsConfig);
+};
+
 module.exports = {
   getTestProjectConfig: getTestProjectConfig,
   getParsedAudiences: getParsedAudiences,
@@ -2497,4 +2586,5 @@ module.exports = {
   getUnsupportedVersionConfig: getUnsupportedVersionConfig,
   getTypedAudiencesConfig: getTypedAudiencesConfig,
   typedAudiencesById: typedAudiencesById,
+  getMutexFeatureTestsConfig: getMutexFeatureTestsConfig,
 };