feat(api): Feature variable APIs return default variable value when featureEnabled property is false. (#159)

Summary:

Feature variable APIs now return default variable value when featureEnabled property is false.

Test plan:

Added unit tests.

Author: rashidsp

src/Optimizely/Optimizely.php

@@ -620,18 +620,26 @@ public function getFeatureVariableValueForType(
             );
         } else {
             $variation = $decision->getVariation();
-            $variable_usage = $variation->getVariableUsageById($variable->getId());
-            if ($variable_usage) {
-                $variableValue = $variable_usage->getValue();
-                $this->_logger->log(
-                    Logger::INFO,
-                    "Returning variable value '{$variableValue}' for variation '{$variation->getKey()}' ".
-                    "of feature flag '{$featureFlagKey}'"
-                );
+            if ($variation->getFeatureEnabled()) {
+                $variableUsage = $variation->getVariableUsageById($variable->getId());
+                if ($variableUsage) {
+                    $variableValue = $variableUsage->getValue();
+                    $this->_logger->log(
+                        Logger::INFO,
+                        "Returning variable value '{$variableValue}' for variation '{$variation->getKey()}' ".
+                        "of feature flag '{$featureFlagKey}'"
+                    );
+                } else {
+                    $this->_logger->log(
+                        Logger::INFO,
+                        "Variable '{$variableKey}' is not used in variation '{$variation->getKey()}', ".
+                        "returning default value '{$variableValue}'."
+                    );
+                }
             } else {
                 $this->_logger->log(
                     Logger::INFO,
-                    "Variable '{$variableKey}' is not used in variation '{$variation->getKey()}', ".
+                    "Feature '{$featureFlagKey}' for variation '{$variation->getKey()}' is not enabled, ".
                     "returning default value '{$variableValue}'."
                 );
             }

tests/OptimizelyTest.php

@@ -2784,6 +2784,45 @@ public function testGetFeatureVariableValueForTypeGivenFeatureFlagIsEnabledForUs
         );
     }
 
+    public function testGetFeatureVariableValueForTypeReturnDefaultVariableValueGivenUserInExperimentAndFeatureFlagIsNotEnabled()
+    {
+        // should return specific value
+        $decisionServiceMock = $this->getMockBuilder(DecisionService::class)
+            ->setConstructorArgs(array($this->loggerMock, $this->projectConfig))
+            ->setMethods(array('getVariationForFeature'))
+            ->getMock();
+
+        $decisionService = new \ReflectionProperty(Optimizely::class, '_decisionService');
+        $decisionService->setAccessible(true);
+        $decisionService->setValue($this->optimizelyObject, $decisionServiceMock);
+
+        $experiment = $this->projectConfig->getExperimentFromKey('test_experiment_double_feature');
+        $variation = $this->projectConfig->getVariationFromKey('test_experiment_double_feature', 'control');
+        $variation->setFeatureEnabled(false);
+        $expectedDecision = new FeatureDecision(
+            $experiment,
+            $variation,
+            FeatureDecision::DECISION_SOURCE_EXPERIMENT
+        );
+
+        $decisionServiceMock->expects($this->exactly(1))
+            ->method('getVariationForFeature')
+            ->will($this->returnValue($expectedDecision));
+
+        $this->loggerMock->expects($this->exactly(1))
+            ->method('log')
+            ->with(
+                Logger::INFO,
+                "Feature 'double_single_variable_feature' for variation 'control' is not enabled, ".
+                "returning default value '14.99'."
+            );
+
+        $this->assertSame(
+            $this->optimizelyObject->getFeatureVariableValueForType('double_single_variable_feature', 'double_variable', 'user_id', [], 'double'),
+            '14.99'
+        );
+    }
+
     public function testGetFeatureVariableValueForTypeWithRolloutRule()
     {
         // should return specific value
@@ -2822,6 +2861,45 @@ public function testGetFeatureVariableValueForTypeWithRolloutRule()
         $this->assertTrue($this->optimizelyObject->getFeatureVariableBoolean('boolean_single_variable_feature', 'boolean_variable', 'user_id', []));
     }
 
+    public function testGetFeatureVariableValueReturnDefaultVariableValueGivenUserInRolloutAndFeatureFlagIsNotEnabled()
+    {
+        // should return specific value
+        $decisionServiceMock = $this->getMockBuilder(DecisionService::class)
+            ->setConstructorArgs(array($this->loggerMock, $this->projectConfig))
+            ->setMethods(array('getVariationForFeature'))
+            ->getMock();
+
+        $decisionService = new \ReflectionProperty(Optimizely::class, '_decisionService');
+        $decisionService->setAccessible(true);
+        $decisionService->setValue($this->optimizelyObject, $decisionServiceMock);
+
+        $featureFlag = $this->projectConfig->getFeatureFlagFromKey('boolean_single_variable_feature');
+        $rolloutId = $featureFlag->getRolloutId();
+        $rollout = $this->projectConfig->getRolloutFromId($rolloutId);
+        $experiment = $rollout->getExperiments()[0];
+        $expectedVariation = $experiment->getVariations()[0];
+        $expectedVariation->setFeatureEnabled(false);
+        $expectedDecision = new FeatureDecision(
+            $experiment,
+            $expectedVariation,
+            FeatureDecision::DECISION_SOURCE_ROLLOUT
+        );
+
+        $decisionServiceMock->expects($this->exactly(1))
+            ->method('getVariationForFeature')
+            ->will($this->returnValue($expectedDecision));
+
+        $this->loggerMock->expects($this->exactly(1))
+            ->method('log')
+            ->with(
+                Logger::INFO,
+                "Feature 'boolean_single_variable_feature' for variation '177771' is not enabled, ".
+                "returning default value 'true'."
+            );
+
+        $this->assertTrue($this->optimizelyObject->getFeatureVariableBoolean('boolean_single_variable_feature', 'boolean_variable', 'user_id', []));
+    }
+
     public function testGetFeatureVariableValueForTypeGivenFeatureFlagIsEnabledForUserAndVariableNotInVariation()
     {
         // should return default value