diff --git a/ruby/tests/well_known_types_test.rb b/ruby/tests/well_known_types_test.rb
index 3eafe095ad0f..044e77c19bd8 100755
--- a/ruby/tests/well_known_types_test.rb
+++ b/ruby/tests/well_known_types_test.rb
@@ -15,16 +15,18 @@ def test_timestamp
 
     # millisecond accuracy
     time = Time.at(123456, 654321)
-    ts.from_time(time)
+    resp = ts.from_time(time)
     assert_equal 123456, ts.seconds
     assert_equal 654321000, ts.nanos
     assert_equal time, ts.to_time
+    assert_equal resp, ts
 
     # nanosecond accuracy
     time = Time.at(123456, Rational(654321321, 1000))
-    ts.from_time(time)
+    resp = ts.from_time(time)
     assert_equal 654321321, ts.nanos
     assert_equal time, ts.to_time
+    assert_equal resp, ts
   end
 
   def test_duration