Merge pull request #207 from nareshnootoo/feature

Adding Number to Voluptuous for validating precision and scale

voluptuous/tests/tests.py

@@ -5,7 +5,7 @@
     Schema, Required, Extra, Invalid, In, Remove, Literal,
     Url, MultipleInvalid, LiteralInvalid, NotIn, Match, Email,
     Replace, Range, Coerce, All, Any, Length, FqdnUrl, ALLOW_EXTRA, PREVENT_EXTRA,
-    validate, ExactSequence, Equal, Unordered
+    validate, ExactSequence, Equal, Unordered, Number
 )
 from voluptuous.humanize import humanize_error
 
@@ -556,3 +556,93 @@ def fn(arg):
         return "hello"
 
     assert_raises(Invalid, fn, 1)
+
+
+def test_number_validation_with_string():
+    """ test with Number with string"""
+    schema = Schema({"number" : Number(precision=6, scale=2)})
+    try:
+        schema({"number": 'teststr'})
+    except MultipleInvalid as e:
+        assert_equal(str(e),
+                     "Value must be a number enclosed with string for dictionary value @ data['number']")
+    else:
+        assert False, "Did not raise Invalid for String"
+
+
+def test_number_validation_with_invalid_precision_invalid_scale():
+    """ test with Number with invalid precision and scale"""
+    schema = Schema({"number" : Number(precision=6, scale=2)})
+    try:
+        schema({"number": '123456.712'})
+    except MultipleInvalid as e:
+        assert_equal(str(e),
+                     "Precision must be equal to 6, and Scale must be equal to 2 for dictionary value @ data['number']")
+    else:
+        assert False, "Did not raise Invalid for String"
+
+
+def test_number_validation_with_valid_precision_scale_yield_decimal_true():
+    """ test with Number with valid precision and scale"""
+    schema = Schema({"number" : Number(precision=6, scale=2, yield_decimal=True)})
+    out_ = schema({"number": '1234.00'})
+    assert_equal(float(out_.get("number")), 1234.00)
+
+
+def test_number_when_precision_scale_none_yield_decimal_true():
+    """ test with Number with no precision and scale"""
+    schema = Schema({"number" : Number(yield_decimal=True)})
+    out_ = schema({"number": '12345678901234'})
+    assert_equal(out_.get("number"), 12345678901234)
+
+
+def test_number_when_precision_none_n_valid_scale_case1_yield_decimal_true():
+    """ test with Number with no precision and valid scale case 1"""
+    schema = Schema({"number" : Number(scale=2, yield_decimal=True)})
+    out_ = schema({"number": '123456789.34'})
+    assert_equal(float(out_.get("number")), 123456789.34)
+
+
+def test_number_when_precision_none_n_valid_scale_case2_yield_decimal_true():
+    """ test with Number with no precision and valid scale case 2 with zero in decimal part"""
+    schema = Schema({"number" : Number(scale=2, yield_decimal=True)})
+    out_ = schema({"number": '123456789012.00'})
+    assert_equal(float(out_.get("number")), 123456789012.00)
+
+
+def test_number_when_precision_none_n_invalid_scale_yield_decimal_true():
+    """ test with Number with no precision and invalid scale"""
+    schema = Schema({"number" : Number(scale=2, yield_decimal=True)})
+    try:
+        schema({"number": '12345678901.234'})
+    except MultipleInvalid as e:
+        assert_equal(str(e),
+                     "Scale must be equal to 2 for dictionary value @ data['number']")
+    else:
+        assert False, "Did not raise Invalid for String"
+
+
+def test_number_when_valid_precision_n_scale_none_yield_decimal_true():
+    """ test with Number with no precision and valid scale"""
+    schema = Schema({"number" : Number(precision=14, yield_decimal=True)})
+    out_ = schema({"number": '1234567.8901234'})
+    assert_equal(float(out_.get("number")), 1234567.8901234)
+
+
+def test_number_when_invalid_precision_n_scale_none_yield_decimal_true():
+    """ test with Number with no precision and invalid scale"""
+    schema = Schema({"number" : Number(precision=14, yield_decimal=True)})
+    try:
+        schema({"number": '12345674.8901234'})
+    except MultipleInvalid as e:
+        assert_equal(str(e),
+                     "Precision must be equal to 14 for dictionary value @ data['number']")
+    else:
+        assert False, "Did not raise Invalid for String"
+
+
+def test_number_validation_with_valid_precision_scale_yield_decimal_false():
+    """ test with Number with valid precision, scale and no yield_decimal"""
+    schema = Schema({"number" : Number(precision=6, scale=2, yield_decimal=False)})
+    out_ = schema({"number": '1234.00'})
+    assert_equal(out_.get("number"), '1234.00')

voluptuous/validators.py

@@ -3,7 +3,7 @@
 import datetime
 import sys
 from functools import wraps
-
+from decimal import Decimal, InvalidOperation
 
 try:
     from schema_builder import Schema, raises, message
@@ -794,3 +794,62 @@ def __call__(self, v):
 
     def __repr__(self):
         return 'Unordered([{}])'.format(", ".join(repr(v) for v in self.validators))
+
+
+class Number(object):
+    """
+    Verify the number of digits that are present in the number(Precision),
+    and the decimal places(Scale)
+
+    :raises Invalid: If the value does not match the provided Precision and Scale.
+
+    >>> schema = Schema(Number(precision=6, scale=2))
+    >>> schema('1234.01')
+    '1234.01'
+    >>> schema = Schema(Number(precision=6, scale=2, yield_decimal=True))
+    >>> schema('1234.01')
+    Decimal('1234.01')
+    """
+
+    def __init__(self, precision=None, scale=None, msg=None, yield_decimal=False):
+        self.precision = precision
+        self.scale = scale
+        self.msg = msg
+        self.yield_decimal = yield_decimal
+
+    def __call__(self, v):
+        """
+        :param v: is a number enclosed with string
+        :return: Decimal number
+        """
+        precision, scale, decimal_num = self._get_precision_scale(v)
+
+        if self.precision is not None and self.scale is not None and\
+            precision != self.precision and scale != self.scale:
+            raise Invalid(self.msg or "Precision must be equal to %s, and Scale must be equal to %s" %(self.precision, self.scale))
+        else:
+            if self.precision is not None and precision != self.precision:
+                raise Invalid(self.msg or "Precision must be equal to %s"%self.precision)
+
+            if self.scale is not None and scale != self.scale :
+                raise Invalid(self.msg or "Scale must be equal to %s"%self.scale)
+
+        if self.yield_decimal:
+            return decimal_num
+        else:
+            return v
+
+    def __repr__(self):
+        return ('Number(precision=%s, scale=%s, msg=%s)' % (self.precision, self.scale, self.msg))
+
+    def _get_precision_scale(self, number):
+        """
+        :param number:
+        :return: tuple(precision, scale, decimal_number)
+        """
+        try:
+            decimal_num = Decimal(number)
+        except InvalidOperation:
+            raise Invalid(self.msg or 'Value must be a number enclosed with string')
+
+        return (len(decimal_num.as_tuple().digits), -(decimal_num.as_tuple().exponent), decimal_num)