add is_number validator

api/validators.py

@@ -10,6 +10,21 @@ def validate_keys_exists(obj, *keys):
     return True
 
 
+def is_number(s):
+    try:
+        float(s)
+        return True
+    except ValueError:
+        return False
+
+
+def validate_number(*values):
+    for val in values:
+        if not is_number(val):
+            raise ValidationError('{} is not a number'.format(val))
+    return True
+
+
 def validate_territory(value):
     for market in iter_markets():
         if market.territory == value:

tests/test_validators.py

@@ -1,5 +1,6 @@
 import unittest2
-from api.validators import ValidationError, validate_keys_exists, validate_territory
+from api.validators import validate_keys_exists, validate_territory, validate_number
+from api.exceptions import ValidationError
 
 
 class TestValidation(unittest2.TestCase):
@@ -15,3 +16,9 @@ class TestValidation(unittest2.TestCase):
     def test_validate_territory(self):
         self.assertTrue(validate_territory('SE'))
         self.assertRaises(ValidationError, validate_territory, 'unknown')
+
+    def test_validate_number(self):
+        self.assertRaises(ValidationError, validate_number, 'foo')
+        self.assertRaises(ValidationError, validate_number, 'foo', 12)
+        self.assertTrue(validate_number(12))
+        self.assertTrue(validate_number(12, 45))