CE Backport: Fix unleash server side cannot return feature flags

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spec/support/helpers/stub_feature_flags.rb

 module StubFeatureFlags
   # Stub Feature flags with `flag_name: true/false`
   #
-  # @param [Hash] features where key is feature name and value is boolean whether enabled or not
+  # @param [Hash] features where key is feature name and value is boolean whether enabled or not.
+  #               Alternatively, you can specify Hash to enable the flag on a specific thing.
+  #
+  # Examples
+  # - `stub_feature_flags(ci_live_trace: false)` ... Disable `ci_live_trace`
+  #   feature flag globally.
+  # - `stub_feature_flags(ci_live_trace: { enabled: false, thing: project })` ...
+  #   Disable `ci_live_trace` feature flag on the specified project.
   def stub_feature_flags(features)
-    features.each do |feature_name, enabled|
+    features.each do |feature_name, option|
+      if option.is_a?(Hash)
+        enabled, thing = option.values_at(:enabled, :thing)
+      else
+        enabled = option
+        thing = nil
+      end
+
+      if thing
+        allow(Feature).to receive(:enabled?).with(feature_name, thing, any_args) { enabled }
+        allow(Feature).to receive(:enabled?).with(feature_name.to_s, thing, any_args) { enabled }
+      else
         allow(Feature).to receive(:enabled?).with(feature_name, any_args) { enabled }
         allow(Feature).to receive(:enabled?).with(feature_name.to_s, any_args) { enabled }
       end
     end
+  end
 end