Fix unit and FSC errors

Author: esrakartalOpt

lib/optimizely/decision_service.rb

@@ -214,6 +214,9 @@ def get_decision_for_flag(feature_flag, user_context, project_config, decide_opt
 
       return DecisionResult.new(experiment_decision.decision, experiment_decision.error, reasons) if experiment_decision.decision
 
+      # If there's an error (e.g., CMAB error), return immediately without falling back to rollout
+      return DecisionResult.new(nil, experiment_decision.error, reasons) if experiment_decision.error
+
       # Check if the feature flag has a rollout and the user is bucketed into that rollout
       rollout_decision = get_variation_for_feature_rollout(project_config, feature_flag, user_context)
       reasons.push(*rollout_decision.reasons)

spec/decision_service_spec.rb

@@ -775,7 +775,7 @@
 
           decision_result = decision_service.get_variation_for_feature(config, feature_flag, user_context)
           expect(decision_result.decision).to eq(expected_decision)
-          expect(decision_result.reasons).to eq([])
+          expect(decision_result.reasons).to eq(["The user 'test_user' is bucketed into a rollout for feature flag 'string_single_variable_feature'."])
         end
       end