bring is_integer into tested existence

Author: benjaminp

Lib/test/test_float.py

@@ -164,6 +164,12 @@ def __float__(self):
         self.assertAlmostEqual(float(FooUnicode('8')), 9.)
         self.assertAlmostEqual(float(FooStr('8')), 9.)
 
+    def test_is_integer(self):
+        self.assertFalse((1.1).is_integer())
+        self.assertTrue((1.).is_integer())
+        self.assertFalse(float("nan").is_integer())
+        self.assertFalse(float("inf").is_integer())
+
     def test_floatasratio(self):
         for f, ratio in [
                 (0.875, (7, 8)),