Add issubset and issuperset methods to the Range type (#563)

asyncpg/types.py

@@ -85,6 +85,39 @@ def upper_inf(self):
     def isempty(self):
         return self._empty
 
+    def _issubset_lower(self, other):
+        if other._lower is None:
+            return True
+        if self._lower is None:
+            return False
+
+        return self._lower > other._lower or (
+            self._lower == other._lower
+            and (other._lower_inc or not self._lower_inc)
+        )
+
+    def _issubset_upper(self, other):
+        if other._upper is None:
+            return True
+        if self._upper is None:
+            return False
+
+        return self._upper < other._upper or (
+            self._upper == other._upper
+            and (other._upper_inc or not self._upper_inc)
+        )
+
+    def issubset(self, other):
+        if self._empty:
+            return True
+        if other._empty:
+            return False
+
+        return self._issubset_lower(other) and self._issubset_upper(other)
+
+    def issuperset(self, other):
+        return other.issubset(self)
+
     def __bool__(self):
         return not self._empty
 

tests/test_types.py

@@ -0,0 +1,56 @@
+# Copyright (C) 2016-present the ayncpg authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of asyncpg and is released under
+# the Apache 2.0 License: http://www.apache.org/licenses/LICENSE-2.0
+
+from itertools import product
+
+from asyncpg.types import Range
+from asyncpg import _testbase as tb
+
+
+class TestTypes(tb.TestCase):
+
+    def test_range_issubset(self):
+        subs = [
+            Range(empty=True),
+            Range(lower=1, upper=5, lower_inc=True, upper_inc=False),
+            Range(lower=1, upper=5, lower_inc=True, upper_inc=True),
+            Range(lower=1, upper=5, lower_inc=False, upper_inc=True),
+            Range(lower=1, upper=5, lower_inc=False, upper_inc=False),
+            Range(lower=-5, upper=10),
+            Range(lower=2, upper=3),
+            Range(lower=1, upper=None),
+            Range(lower=None, upper=None)
+        ]
+
+        sups = [
+            Range(empty=True),
+            Range(lower=1, upper=5, lower_inc=True, upper_inc=False),
+            Range(lower=1, upper=5, lower_inc=True, upper_inc=True),
+            Range(lower=1, upper=5, lower_inc=False, upper_inc=True),
+            Range(lower=1, upper=5, lower_inc=False, upper_inc=False),
+            Range(lower=None, upper=None)
+        ]
+
+        # Each row is 1 subs with all sups
+        results = [
+            True, True, True, True, True, True,
+            False, True, True, False, False, True,
+            False, False, True, False, False, True,
+            False, False, True, True, False, True,
+            False, True, True, True, True, True,
+            False, False, False, False, False, True,
+            False, True, True, True, True, True,
+            False, False, False, False, False, True,
+            False, False, False, False, False, True
+        ]
+
+        for (sub, sup), res in zip(product(subs, sups), results):
+            self.assertIs(
+                sub.issubset(sup), res, "Sub:{}, Sup:{}".format(sub, sup)
+            )
+            self.assertIs(
+                sup.issuperset(sub), res, "Sub:{}, Sup:{}".format(sub, sup)
+            )