Add PositiveIntegerValue to only allow positive integers (#186)

jazzband · Mar 15, 2018 · 1c6fd0f · jezdez · Jul 11, 2018 · blueyed
1 parent 3883cc4
commit 1c6fd0f
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Showing 3 changed files with 27 additions and 1 deletion.
diff --git a/configurations/values.py b/configurations/values.py
@@ -178,6 +178,15 @@ class IntegerValue(CastingMixin, Value):
     caster = int
 
 
+class PositiveIntegerValue(IntegerValue):
+
+    def to_python(self, value):
+        int_value = super(PositiveIntegerValue, self).to_python(value)
+        if int_value < 0:
+            raise ValueError(self.message.format(value))
+        return int_value
+
+
 class FloatValue(CastingMixin, Value):
     caster = float
 

diff --git a/docs/values.rst b/docs/values.rst
@@ -230,6 +230,14 @@ Type values
 
         MYSITE_CACHE_TIMEOUT = values.IntegerValue(3600)
 
+.. class:: PositiveIntegerValue
+
+    A :class:`~Value` subclass that handles positive integer values.
+
+    ::
+
+        MYSITE_WORKER_POOL = values.PositiveIntegerValue(8)
+
 .. class:: FloatValue
 
     A :class:`~Value` subclass that handles float values.

diff --git a/tests/test_values.py b/tests/test_values.py
@@ -16,7 +16,7 @@
                                    DatabaseURLValue, EmailURLValue,
                                    CacheURLValue, BackendsValue,
                                    CastingMixin, SearchURLValue,
-                                   setup_value)
+                                   setup_value, PositiveIntegerValue)
 
 
 @contextmanager
@@ -136,6 +136,15 @@ def test_integer_values(self):
         with env(DJANGO_TEST='noninteger'):
             self.assertRaises(ValueError, value.setup, 'TEST')
 
+    def test_positive_integer_values(self):
+        value = PositiveIntegerValue(1)
+        with env(DJANGO_TEST='2'):
+            self.assertEqual(value.setup('TEST'), 2)
+        with env(DJANGO_TEST='noninteger'):
+            self.assertRaises(ValueError, value.setup, 'TEST')
+        with env(DJANGO_TEST='-1'):
+            self.assertRaises(ValueError, value.setup, 'TEST')
+
     def test_float_values(self):
         value = FloatValue(1.0)
         with env(DJANGO_TEST='2.0'):