test_fluentd: add --disable-input-metrics test

Signed-off-by: Shizuo Fujita <fujita@clear-code.com>

Author: Watson1978

test/command/test_fluentd.rb

@@ -1608,4 +1608,16 @@ def create_config_include_dir_configuration(config_path, config_dir, yaml_format
                          "[info]: loading additional configuration file path=\"#{conf_dir}/child.yml\"")
     end
   end
+
+  test "allow --disable-input-metrics option" do
+    conf = <<CONF
+<system>
+</system>
+CONF
+    conf_path = create_conf_file('input-metrics.conf', conf)
+    assert_log_matches(
+      create_cmdline(conf_path, '--disable-input-metrics'),
+      "#0 fluentd worker is now running worker=0"
+    )
+  end
 end