use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
index 1943518..494014e 100644
--- a/Lib/test/test_long.py
+++ b/Lib/test/test_long.py
@@ -552,7 +552,7 @@
             y = int(x)
         except OverflowError:
             self.fail("int(long(sys.maxint) + 1) mustn't overflow")
-        self.assertTrue(isinstance(y, long),
+        self.assertIsInstance(y, long,
             "int(long(sys.maxint) + 1) should have returned long")
 
         x = hugeneg_aslong - 1
@@ -560,7 +560,7 @@
             y = int(x)
         except OverflowError:
             self.fail("int(long(-sys.maxint-1) - 1) mustn't overflow")
-        self.assertTrue(isinstance(y, long),
+        self.assertIsInstance(y, long,
                "int(long(-sys.maxint-1) - 1) should have returned long")
 
         class long2(long):