Improved NumberRange handling

sqlalchemy_utils/primitives/number_range.py

@@ -65,7 +65,8 @@ class NumberRange(object):
     def lower(self, value):
         if value is None:
             self._lower = -float('inf')
-        self._lower = value
+        else:
+            self._lower = value
 
     @property
     def upper(self):
@@ -75,7 +76,22 @@ class NumberRange(object):
     def upper(self, value):
         if value is None:
             self._upper = float('inf')
-        self._upper = value
+        else:
+            self._upper = value
+
+    @property
+    def open(self):
+        """
+        Returns whether or not this object is an open interval.
+        """
+        return not self.lower_inc and not self.upper_inc
+
+    @property
+    def closed(self):
+        """
+        Returns whether or not this object is a closed interval.
+        """
+        return self.lower_inc and self.upper_inc
 
     def parse_object(self, obj):
         self.lower = obj.lower
@@ -93,7 +109,10 @@ class NumberRange(object):
         lower, upper = seq
         self.lower = parse_number(lower)
         self.upper = parse_number(upper)
-        self.lower_inc = self.upper_inc = True
+        if isinstance(seq, tuple):
+            self.lower_inc = self.upper_inc = False
+        else:
+            self.lower_inc = self.upper_inc = True
 
     def parse_integer(self, value):
         self.lower = self.upper = value
@@ -125,14 +144,8 @@ class NumberRange(object):
         except ValueError as e:
             raise NumberRangeException(e.message)
 
-        self.lower_inc = value[0] == '('
+        self.lower_inc = value[0] == '['
-        if self.lower_inc:
+        self.upper_inc = value[-1] == ']'
-            lower += 1
-
-        self.upper_inc = value[-1] == ')'
-        if self.upper_inc:
-            upper -= 1
-
         self.lower = lower
         self.upper = upper
 
@@ -151,9 +164,11 @@ class NumberRange(object):
 
     @property
     def normalized(self):
-        return '[%s, %s]' % (
+        return '%s%s, %s%s' % (
-            self.lower if self.lower is not None else '',
+            '[' if self.lower_inc else '(',
-            self.upper if self.upper is not None else ''
+            self.lower if self.lower != -float('inf') else '',
+            self.upper if self.upper != float('inf') else '',
+            ']' if self.upper_inc else ')'
         )
 
     def __eq__(self, other):

tests/primitives/test_number_range.py

@@ -30,6 +30,11 @@ class TestNumberRangeInit(object):
         assert num_range.lower == 1
         assert num_range.upper == 3
 
+    def test_empty_string_as_upper_bound(self):
+        num_range = NumberRange('[1,)')
+        assert num_range.lower == 1
+        assert num_range.upper == float('inf')
+
     def test_supports_exact_ranges_as_strings(self):
         num_range = NumberRange('3')
         assert num_range.lower == 3
@@ -93,6 +98,36 @@ def test_raises_exception_for_badly_constructed_range(number_range):
         NumberRange(number_range)
 
 
+@mark.parametrize(('number_range', 'is_open'),
+    (
+        ((2, 3), True),
+        ('(2, 5)', True),
+        ('[3, 4)', False),
+        ('(4, 5]', False),
+        ('3 - 4', False),
+        ([4, 5], False),
+        ('[4, 5]', False)
+    )
+)
+def test_open(number_range, is_open):
+    assert NumberRange(number_range).open == is_open
+
+
+@mark.parametrize(('number_range', 'is_closed'),
+    (
+        ((2, 3), False),
+        ('(2, 5)', False),
+        ('[3, 4)', False),
+        ('(4, 5]', False),
+        ('3 - 4', True),
+        ([4, 5], True),
+        ('[4, 5]', True)
+    )
+)
+def test_closed(number_range, is_closed):
+    assert NumberRange(number_range).closed == is_closed
+
+
 class TestArithmeticOperators(object):
     def test_add_operator(self):
         assert NumberRange(1, 2) + NumberRange(1, 2) == NumberRange(2, 4)

tests/types/test_number_range.py

@@ -36,9 +36,10 @@ class TestNumberRangeType(TestCase):
         )
         self.session.add(building)
         self.session.commit()
+
         building = self.session.query(self.Building).first()
         assert building.persons_at_night.lower == 1
-        assert building.persons_at_night.upper is None
+        assert building.persons_at_night.upper == float('inf')
 
     def test_infinite_lower_bound(self):
         building = self.Building(
@@ -47,8 +48,8 @@ class TestNumberRangeType(TestCase):
         self.session.add(building)
         self.session.commit()
         building = self.session.query(self.Building).first()
-        assert building.persons_at_night.lower is None
+        assert building.persons_at_night.lower == -float('inf')
-        assert building.persons_at_night.upper is 1
+        assert building.persons_at_night.upper == 1
 
     def test_nullify_number_range(self):
         building = self.Building(