Issue 2690: Add support for slicing and negative indices to range objects (includes precalculation and storage of the range length).

Refer to the tracker issue for the language moratorium implications of this change

1 files changed, 72 insertions, 1 deletions

diff --git a/Lib/test/test_range.py b/Lib/test/test_range.py
index 5cbc11b..5aa5920 100644
--- a/Lib/test/test_range.py
+++ b/Lib/test/test_range.py
@@ -136,7 +136,12 @@ class RangeTest(unittest.TestCase):
         self.assertNotIn(-b, seq)
         self.assertEqual(len(seq), 2)
 
-        self.assertRaises(OverflowError, len, range(0, sys.maxsize**10))
+        self.assertRaises(OverflowError, len,
+                          range(-sys.maxsize, sys.maxsize))
+        self.assertRaises(OverflowError, len,
+                          range(0, 2*sys.maxsize))
+        self.assertRaises(OverflowError, len,
+                          range(0, sys.maxsize**10))
 
     def test_invalid_invocation(self):
         self.assertRaises(TypeError, range)
@@ -248,6 +253,8 @@ class RangeTest(unittest.TestCase):
         always_equal = AlwaysEqual()
         self.assertEqual(range(10).count(always_equal), 10)
 
+        self.assertEqual(len(range(sys.maxsize, sys.maxsize+10)), 10)
+
     def test_repr(self):
         self.assertEqual(repr(range(1)), 'range(0, 1)')
         self.assertEqual(repr(range(1, 2)), 'range(1, 2)')
@@ -349,6 +356,70 @@ class RangeTest(unittest.TestCase):
             test_id = "reversed(range({}, {}, {}))".format(start, end, step)
             self.assert_iterators_equal(iter1, iter2, test_id, limit=100)
 
+    def test_slice(self):
+        def check(start, stop, step=None):
+            i = slice(start, stop, step)
+            self.assertEqual(list(r[i]), list(r)[i])
+            self.assertEqual(len(r[i]), len(list(r)[i]))
+        for r in [range(10),
+                  range(0),
+                  range(1, 9, 3),
+                  range(8, 0, -3),
+                  range(sys.maxsize+1, sys.maxsize+10),
+                  ]:
+            check(0, 2)
+            check(0, 20)
+            check(1, 2)
+            check(20, 30)
+            check(-30, -20)
+            check(-1, 100, 2)
+            check(0, -1)
+            check(-1, -3, -1)
+
+    def test_contains(self):
+        r = range(10)
+        self.assertIn(0, r)
+        self.assertIn(1, r)
+        self.assertIn(5.0, r)
+        self.assertNotIn(5.1, r)
+        self.assertNotIn(-1, r)
+        self.assertNotIn(10, r)
+        self.assertNotIn("", r)
+        r = range(9, -1, -1)
+        self.assertIn(0, r)
+        self.assertIn(1, r)
+        self.assertIn(5.0, r)
+        self.assertNotIn(5.1, r)
+        self.assertNotIn(-1, r)
+        self.assertNotIn(10, r)
+        self.assertNotIn("", r)
+        r = range(0, 10, 2)
+        self.assertIn(0, r)
+        self.assertNotIn(1, r)
+        self.assertNotIn(5.0, r)
+        self.assertNotIn(5.1, r)
+        self.assertNotIn(-1, r)
+        self.assertNotIn(10, r)
+        self.assertNotIn("", r)
+        r = range(9, -1, -2)
+        self.assertNotIn(0, r)
+        self.assertIn(1, r)
+        self.assertIn(5.0, r)
+        self.assertNotIn(5.1, r)
+        self.assertNotIn(-1, r)
+        self.assertNotIn(10, r)
+        self.assertNotIn("", r)
+
+    def test_reverse_iteration(self):
+        for r in [range(10),
+                  range(0),
+                  range(1, 9, 3),
+                  range(8, 0, -3),
+                  range(sys.maxsize+1, sys.maxsize+10),
+                  ]:
+            self.assertEqual(list(reversed(r)), list(r)[::-1])
+
+
 def test_main():
     test.support.run_unittest(RangeTest)