Using appropriate checks in tests

Lib/test/test_gc.py

 import unittest
 from test.support import (verbose, refcount_test, run_unittest,
                             strip_python_stderr, cpython_only)
 from test.script_helper import assert_python_ok, make_script, temp_dir
 
 import sys
 import time
 import gc
 import weakref
 
@@ skipping 746 matching lines @@
         # Count that we got the right number of start and stop callbacks.
         n = [v[1] for v in self.visit]
         n1 = [i for i in n if i == "start"]
         n2 = [i for i in n if i == "stop"]
         self.assertEqual(n1, ["start"]*2)
         self.assertEqual(n2, ["stop"]*2)
 
         # Check that we got the right info dict for all callbacks
         for v in self.visit:
             info = v[2]
-            self.assertTrue("generation" in info)
-            self.assertTrue("collected" in info)
-            self.assertTrue("uncollectable" in info)
+            self.assertIn("generation", info)
+            self.assertIn("collected", info)
+            self.assertIn("uncollectable", info)
 
     def test_collect_generation(self):
         self.preclean()
         gc.collect(2)
         for v in self.visit:
             info = v[2]
             self.assertEqual(info["generation"], 2)
 
     @cpython_only
     def test_collect_garbage(self):
@@ skipping 192 matching lines @@
         if verbose:
             print("restoring automatic collection")
         # make sure to always test gc.enable()
         gc.enable()
         assert gc.isenabled()
         if not enabled:
             gc.disable()
 
 if __name__ == "__main__":
     test_main()