Add a predicate to check for strong memoization

lib/gitlab/utils/strong_memoize.rb

@@ -24,13 +24,17 @@ module Gitlab
       #     end
       #
       def strong_memoize(name)
-        if instance_variable_defined?(ivar(name))
+        if strong_memoized?(name)
           instance_variable_get(ivar(name))
         else
           instance_variable_set(ivar(name), yield)
         end
       end
 
+      def strong_memoized?(name)
+        instance_variable_defined?(ivar(name))
+      end
+
       def clear_memoization(name)
         remove_instance_variable(ivar(name)) if instance_variable_defined?(ivar(name))
       end

spec/lib/gitlab/utils/strong_memoize_spec.rb

@@ -52,6 +52,22 @@ describe Gitlab::Utils::StrongMemoize do
     end
   end
 
+  describe '#strong_memoized?' do
+    let(:value) { :anything }
+
+    subject { object.strong_memoized?(:method_name) }
+
+    it 'returns false if the value is uncached' do
+      is_expected.to be(false)
+    end
+
+    it 'returns true if the value is cached' do
+      object.method_name
+
+      is_expected.to be(true)
+    end
+  end
+
   describe '#clear_memoization' do
     let(:value) { 'mepmep' }