RCBC-441: allow nil values for duration extractor (#111)

Author: avsej

lib/couchbase/utils/time.rb

@@ -55,7 +55,8 @@ def extract_expiry_time(time_or_duration)
       #    then use it and convert result to Integer
       # 3. Otherwise invoke #to_i on the argument and interpret it as a number of milliseconds
       def extract_duration(number_or_duration)
-        return number_or_duration if number_or_duration.is_a? Integer
+        return unless number_or_duration
+        return number_or_duration if number_or_duration.class == Integer # rubocop:disable Style/ClassEqualityComparison avoid overrides of #is_a?, #kind_of?
 
         if number_or_duration.respond_to?(:in_milliseconds)
           number_or_duration.public_send(:in_milliseconds)

test/utils_time_test.rb

@@ -51,4 +51,8 @@ def test_accepts_floats
   def test_interpret_integer_as_a_milliseconds_literal
     assert_equal 42, Couchbase::Utils::Time.extract_duration(42)
   end
+
+  def test_ignores_nil_argument
+    assert_nil Couchbase::Utils::Time.extract_duration(nil)
+  end
 end