✨ Add currency code ISO4217 (#143)

* Add currency code ISO 4217 and its subset that includes only currencies

* added ISO 4217
* added tests

* ♻️ Update currency code parsing

---------

Co-authored-by: 07pepa <“[email protected]”>
Co-authored-by: Yasser Tahiri <[email protected]>

Author: 3 people

pydantic_extra_types/currency_code.py

@@ -0,0 +1,179 @@
+"""
+Currency definitions that are based on the [ISO4217](https://en.wikipedia.org/wiki/ISO_4217).
+"""
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import GetCoreSchemaHandler, GetJsonSchemaHandler
+from pydantic_core import PydanticCustomError, core_schema
+
+try:
+    import pycountry
+except ModuleNotFoundError:  # pragma: no cover
+    raise RuntimeError(
+        'The `currency_code` module requires "pycountry" to be installed. You can install it with "pip install '
+        'pycountry".'
+    )
+
+# List of codes that should not be usually used within regular transactions
+_CODES_FOR_BONDS_METAL_TESTING = {
+    'XTS',  # testing
+    'XAU',  # gold
+    'XAG',  # silver
+    'XPD',  # palladium
+    'XPT',  # platinum
+    'XBA',  # Bond Markets Unit European Composite Unit (EURCO)
+    'XBB',  # Bond Markets Unit European Monetary Unit (E.M.U.-6)
+    'XBC',  # Bond Markets Unit European Unit of Account 9 (E.U.A.-9)
+    'XBD',  # Bond Markets Unit European Unit of Account 17 (E.U.A.-17)
+    'XXX',  # no currency
+    'XDR',  # SDR (Special Drawing Right)
+}
+
+
+class ISO4217(str):
+    """ISO4217 parses Currency in the [ISO 4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+
+    ```py
+    from pydantic import BaseModel
+
+    from pydantic_extra_types.currency_code import ISO4217
+
+    class Currency(BaseModel):
+        alpha_3: ISO4217
+
+    currency = Currency(alpha_3='AED')
+    print(currency)
+    # > alpha_3='AED'
+    ```
+    """
+
+    allowed_countries_list = [country.alpha_3 for country in pycountry.currencies]
+    allowed_currencies = set(allowed_countries_list)
+
+    @classmethod
+    def _validate(cls, currency_code: str, _: core_schema.ValidationInfo) -> str:
+        """
+        Validate a ISO 4217 language code from the provided str value.
+
+        Args:
+            currency_code: The str value to be validated.
+            _: The Pydantic ValidationInfo.
+
+        Returns:
+            The validated ISO 4217 currency code.
+
+        Raises:
+            PydanticCustomError: If the ISO 4217 currency code is not valid.
+        """
+        if currency_code not in cls.allowed_currencies:
+            raise PydanticCustomError(
+                'ISO4217', 'Invalid ISO 4217 currency code. See https://en.wikipedia.org/wiki/ISO_4217'
+            )
+        return currency_code
+
+    @classmethod
+    def __get_pydantic_core_schema__(cls, _: type[Any], __: GetCoreSchemaHandler) -> core_schema.CoreSchema:
+        return core_schema.with_info_after_validator_function(
+            cls._validate,
+            core_schema.str_schema(min_length=3, max_length=3),
+        )
+
+    @classmethod
+    def __get_pydantic_json_schema__(
+        cls, schema: core_schema.CoreSchema, handler: GetJsonSchemaHandler
+    ) -> dict[str, Any]:
+        json_schema = handler(schema)
+        json_schema.update({'enum': cls.allowed_countries_list})
+        return json_schema
+
+
+class Currency(str):
+    """Currency parses currency subset of the [ISO 4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+    It excludes bonds testing codes and precious metals.
+        ```py
+        from pydantic import BaseModel
+
+        from pydantic_extra_types.currency_code import Currency
+
+        class currency(BaseModel):
+            alpha_3: Currency
+
+        cur = currency(alpha_3='AED')
+        print(cur)
+        # > alpha_3='AED'
+        ```
+    """
+
+    allowed_countries_list = list(
+        filter(lambda x: x not in _CODES_FOR_BONDS_METAL_TESTING, ISO4217.allowed_countries_list)
+    )
+    allowed_currencies = set(allowed_countries_list)
+
+    @classmethod
+    def _validate(cls, currency_symbol: str, _: core_schema.ValidationInfo) -> str:
+        """
+        Validate a subset of the [ISO4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+        It excludes bonds testing codes and precious metals.
+
+        Args:
+            currency_symbol: The str value to be validated.
+            _: The Pydantic ValidationInfo.
+
+        Returns:
+            The validated ISO 4217 currency code.
+
+        Raises:
+            PydanticCustomError: If the ISO 4217 currency code is not valid or is bond, precious metal or testing code.
+        """
+        if currency_symbol not in cls.allowed_currencies:
+            raise PydanticCustomError(
+                'InvalidCurrency',
+                'Invalid currency code.'
+                ' See https://en.wikipedia.org/wiki/ISO_4217. '
+                'Bonds, testing and precious metals codes are not allowed.',
+            )
+        return currency_symbol
+
+    @classmethod
+    def __get_pydantic_core_schema__(cls, _: type[Any], __: GetCoreSchemaHandler) -> core_schema.CoreSchema:
+        """
+        Return a Pydantic CoreSchema with the currency subset of the
+        [ISO4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+        It excludes bonds testing codes and precious metals.
+
+         Args:
+             _: The source type.
+             __: The handler to get the CoreSchema.
+
+         Returns:
+            A Pydantic CoreSchema with the subset of the currency subset of the
+            [ISO4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+            It excludes bonds testing codes and precious metals.
+        """
+        return core_schema.with_info_after_validator_function(
+            cls._validate,
+            core_schema.str_schema(min_length=3, max_length=3),
+        )
+
+    @classmethod
+    def __get_pydantic_json_schema__(
+        cls, schema: core_schema.CoreSchema, handler: GetJsonSchemaHandler
+    ) -> dict[str, Any]:
+        """
+        Return a Pydantic JSON Schema with subset of the [ISO4217](https://en.wikipedia.org/wiki/ISO_4217) format.
+        Excluding bonds testing codes and precious metals.
+
+        Args:
+            schema: The Pydantic CoreSchema.
+            handler: The handler to get the JSON Schema.
+
+        Returns:
+            A Pydantic JSON Schema with the subset of the ISO4217 currency code validation. without bonds testing codes
+            and precious metals.
+
+        """
+        json_schema = handler(schema)
+        json_schema.update({'enum': cls.allowed_countries_list})
+        return json_schema

tests/test_currency_code.py

@@ -0,0 +1,64 @@
+import re
+
+import pycountry
+import pytest
+from pydantic import BaseModel, ValidationError
+
+from pydantic_extra_types import currency_code
+
+
+class ISO4217CheckingModel(BaseModel):
+    currency: currency_code.ISO4217
+
+
+class CurrencyCheckingModel(BaseModel):
+    currency: currency_code.Currency
+
+
+forbidden_currencies = sorted(currency_code._CODES_FOR_BONDS_METAL_TESTING)
+
+
+@pytest.mark.parametrize('currency', map(lambda code: code.alpha_3, pycountry.currencies))
+def test_ISO4217_code_ok(currency: str):
+    model = ISO4217CheckingModel(currency=currency)
+    assert model.currency == currency
+    assert model.model_dump() == {'currency': currency}  # test serialization
+
+
+@pytest.mark.parametrize(
+    'currency',
+    filter(
+        lambda code: code not in currency_code._CODES_FOR_BONDS_METAL_TESTING,
+        map(lambda code: code.alpha_3, pycountry.currencies),
+    ),
+)
+def test_everyday_code_ok(currency: str):
+    model = CurrencyCheckingModel(currency=currency)
+    assert model.currency == currency
+    assert model.model_dump() == {'currency': currency}  # test serialization
+
+
+def test_ISO4217_fails():
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            '1 validation error for ISO4217CheckingModel\ncurrency\n  '
+            'Invalid ISO 4217 currency code. See https://en.wikipedia.org/wiki/ISO_4217 '
+            "[type=ISO4217, input_value='OMG', input_type=str]"
+        ),
+    ):
+        ISO4217CheckingModel(currency='OMG')
+
+
+@pytest.mark.parametrize('forbidden_currency', forbidden_currencies)
+def test_forbidden_everyday(forbidden_currency):
+    with pytest.raises(
+        ValidationError,
+        match=re.escape(
+            '1 validation error for CurrencyCheckingModel\ncurrency\n  '
+            'Invalid currency code. See https://en.wikipedia.org/wiki/ISO_4217. '
+            'Bonds, testing and precious metals codes are not allowed. '
+            f"[type=InvalidCurrency, input_value='{forbidden_currency}', input_type=str]"
+        ),
+    ):
+        CurrencyCheckingModel(currency=forbidden_currency)

tests/test_json_schema.py

@@ -2,6 +2,7 @@
 import pytest
 from pydantic import BaseModel
 
+import pydantic_extra_types
 from pydantic_extra_types.color import Color
 from pydantic_extra_types.coordinate import Coordinate, Latitude, Longitude
 from pydantic_extra_types.country import (
@@ -10,6 +11,7 @@
     CountryNumericCode,
     CountryShortName,
 )
+from pydantic_extra_types.currency_code import ISO4217, Currency
 from pydantic_extra_types.isbn import ISBN
 from pydantic_extra_types.language_code import ISO639_3, ISO639_5
 from pydantic_extra_types.mac_address import MacAddress
@@ -22,6 +24,16 @@
 languages.sort()
 language_families.sort()
 
+currencies = [currency.alpha_3 for currency in pycountry.currencies]
+currencies.sort()
+everyday_currencies = [
+    currency.alpha_3
+    for currency in pycountry.currencies
+    if currency.alpha_3 not in pydantic_extra_types.currency_code._CODES_FOR_BONDS_METAL_TESTING
+]
+
+everyday_currencies.sort()
+
 
 @pytest.mark.parametrize(
     'cls,expected',
@@ -241,6 +253,40 @@
                 'type': 'object',
             },
         ),
+        (
+            ISO4217,
+            {
+                'properties': {
+                    'x': {
+                        'title': 'X',
+                        'type': 'string',
+                        'enum': currencies,
+                        'maxLength': 3,
+                        'minLength': 3,
+                    }
+                },
+                'required': ['x'],
+                'title': 'Model',
+                'type': 'object',
+            },
+        ),
+        (
+            Currency,
+            {
+                'properties': {
+                    'x': {
+                        'title': 'X',
+                        'type': 'string',
+                        'enum': everyday_currencies,
+                        'maxLength': 3,
+                        'minLength': 3,
+                    }
+                },
+                'required': ['x'],
+                'title': 'Model',
+                'type': 'object',
+            },
+        ),
     ],
 )
 def test_json_schema(cls, expected):