code: def test_metrics(self):
      metrics = self.font.metrics()
      self.assertGreaterEqual(
          set(metrics), {"ascent", "descent", "linespace", "fixed"}
      )
      for key in metrics:
          self.assertEqual(self.font.metrics(key), metrics[key])
          self.assertIsInstance(metrics[key], int)
          self.assertIsInstance(self.font.metrics(key), int)
  
imports: import unittest
  import tkinter
  from tkinter import font
  from test.support import requires, gc_collect, ALWAYS_EQ
  from test.test_tkinter.support import AbstractTkTest, AbstractDefaultRootTest
label_desc: Use image node_id 8 for calling the FontTest obj's underlying member method code with example usage: obj.test_metrics() without return types