fix: When rollout has no rule, should return null

OptimizelySDK.Tests/DecisionServiceTest.cs

@@ -569,6 +569,24 @@ public void TestGetVariationForFeatureExperimentGivenMutexGroupAndUserNotBuckete
         #region GetVariationForFeatureRollout Tests
 
         // Should return null when rollout doesn't exist for the feature.
+        [Test]
+        public void TestGetVariationForFeatureRolloutWhenNoRuleInRollouts()
+        {
+            var projectConfig = DatafileProjectConfig.Create(TestData.EmptyRolloutDatafile, new NoOpLogger(), new NoOpErrorHandler());
+
+            Assert.IsNotNull(projectConfig);
+            var featureFlag = projectConfig.FeatureKeyMap["empty_rollout"];
+            var rollout = projectConfig.GetRolloutFromId(featureFlag.RolloutId);
+
+            Assert.AreEqual(rollout.Experiments.Count, 0);
+
+            var decisionService = new DecisionService(new Bucketer(new NoOpLogger()), new NoOpErrorHandler(), null, new NoOpLogger());
+
+            var variation = decisionService.GetVariationForFeatureRollout(featureFlag, "userId1", null, projectConfig);
+
+            Assert.IsNull(variation);
+        }
+
         [Test]
         public void TestGetVariationForFeatureRolloutWhenRolloutIsNotInDataFile()
         {

OptimizelySDK.Tests/EmptyRolloutRule.json

@@ -0,0 +1,44 @@
+{
+  "version": "4",
+  "rollouts": [
+    {
+      "experiments": [
+      ],
+      "id": "18309384009"
+    }
+  ],
+  "typedAudiences": [],
+  "anonymizeIP": true,
+  "projectId": "18326250003",
+  "variables": [],
+  "featureFlags": [
+    {
+      "experimentIds": [],
+      "rolloutId": "18309384009",
+      "variables": [
+        {
+          "defaultValue": "",
+          "type": "string",
+          "id": "18323951833",
+          "key": "var_1"
+        }
+      ],
+      "id": "18244658520",
+      "key": "empty_rollout"
+    }
+  ],
+  "experiments": [],
+  "audiences": [
+    {
+      "conditions": "[\"or\", {\"match\": \"exact\", \"name\": \"$opt_dummy_attribute\", \"type\": \"custom_attribute\", \"value\": \"$opt_dummy_value\"}]",
+      "id": "$opt_dummy_audience",
+      "name": "Optimizely-Generated Audience for Backwards Compatibility"
+    }
+  ],
+  "groups": [],
+  "attributes": [],
+  "botFiltering": false,
+  "accountId": "8272261422",
+  "events": [],
+  "revision": "2"
+}

OptimizelySDK.Tests/OptimizelySDK.Tests.csproj

@@ -119,6 +119,7 @@
   <ItemGroup>
     <EmbeddedResource Include="TestData.json" />
     <EmbeddedResource Include="simple_ab_experiments.json" />
+    <EmbeddedResource Include="EmptyRolloutRule.json" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OptimizelySDK\OptimizelySDK.csproj">

OptimizelySDK.Tests/Utils/TestData.cs

@@ -27,6 +27,7 @@ public class TestData
         private static string simpleABExperimentsDatafile = null;
         private static string unsupportedVersionDatafile = null;
         private static string typedAudienceDatafile = null;
+        private static string emptyRolloutDatafile = null;
 
         public static string Datafile
         {
@@ -52,6 +53,12 @@ public static string UnsupportedVersionDatafile
             }
         }
 
+        public static string EmptyRolloutDatafile {
+            get {
+                return emptyRolloutDatafile ?? (emptyRolloutDatafile = LoadJsonData("EmptyRolloutRule.json"));
+            }
+        }
+
         public static string TypedAudienceDatafile
         {
             get

OptimizelySDK/Bucketing/DecisionService.cs

@@ -389,6 +389,10 @@ public virtual FeatureDecision GetVariationForFeatureRollout(FeatureFlag feature
                 return null;
             }
 
+            if (rollout.Experiments == null ||  rollout.Experiments.Count == 0) {
+                return null;
+            }
+
             Variation variation = null;
             var rolloutRulesLength = rollout.Experiments.Count;