[ruby/etc] Prefer dedicated assertions

ruby/etc@9caddede76

Author: nobu

test/etc/test_etc.rb

@@ -21,7 +21,7 @@ def test_passwd
       assert_instance_of(String, s.shell)
       assert_kind_of(Integer, s.change) if s.respond_to?(:change)
       assert_kind_of(Integer, s.quota) if s.respond_to?(:quota)
-      assert(s.age.is_a?(Integer) || s.age.is_a?(String)) if s.respond_to?(:age)
+      assert(s.age.is_a?(Integer) || s.age.is_a?(String), s.age) if s.respond_to?(:age)
       assert_instance_of(String, s.uclass) if s.respond_to?(:uclass)
       assert_instance_of(String, s.comment) if s.respond_to?(:comment)
       assert_kind_of(Integer, s.expire) if s.respond_to?(:expire)
@@ -160,7 +160,7 @@ def test_pathconf
     end
     IO.pipe {|r, w|
       val = w.pathconf(Etc::PC_PIPE_BUF)
-      assert(val.nil? || val.kind_of?(Integer))
+      assert_kind_of(Integer, val) if val
     }
   end if defined?(Etc::PC_PIPE_BUF)