feat: allow comparing currency values to currency strings (#2149)

src/ape/api/address.py

@@ -3,7 +3,7 @@
 from eth_pydantic_types import HexBytes
 
 from ape.exceptions import ConversionError
-from ape.types import AddressType, ContractCode
+from ape.types import AddressType, ContractCode, CurrencyValue
 from ape.utils import BaseInterface, abstractmethod, cached_property, log_instead_of_fail
 
 if TYPE_CHECKING:
@@ -119,8 +119,10 @@ def balance(self) -> int:
         """
         The total balance of the account.
         """
-
-        return self.provider.get_balance(self.address)
+        bal = self.provider.get_balance(self.address)
+        # By using CurrencyValue, we can compare with
+        # strings like "1 ether".
+        return CurrencyValue(bal)
 
     # @balance.setter
     # NOTE: commented out because of failure noted within `__setattr__`

src/ape/types/__init__.py

@@ -36,6 +36,7 @@
     BaseInterfaceModel,
     ExtraAttributesMixin,
     ExtraModelAttributes,
+    ManagerAccessMixin,
     cached_property,
 )
 from ape.utils.misc import ZERO_ADDRESS, log_instead_of_fail, to_int
@@ -470,6 +471,23 @@ def generator(self) -> Iterator:
         yield from self._generator
 
 
+class CurrencyValue(int):
+    """
+    An integer you can compare with currency-value
+    strings, such as ``"1 ether"``.
+    """
+
+    def __eq__(self, other: Any) -> bool:
+        if isinstance(other, int):
+            return super().__eq__(other)
+        elif isinstance(other, str):
+            other_value = ManagerAccessMixin.conversion_manager.convert(other, int)
+            return super().__eq__(other_value)
+
+        # Try from the other end, if hasn't already.
+        return NotImplemented
+
+
 __all__ = [
     "ABI",
     "AddressType",
@@ -487,6 +505,7 @@ def generator(self) -> Iterator:
     "CoverageProject",
     "CoverageReport",
     "CoverageStatement",
+    "CurrencyValue",
     "GasReport",
     "MessageSignature",
     "PackageManifest",

src/ape_ethereum/_converters.py

@@ -1,6 +1,7 @@
 from decimal import Decimal
 
-from ape.api import ConverterAPI
+from ape.api.convert import ConverterAPI
+from ape.types import CurrencyValue
 
 ETHER_UNITS = {
     "eth": int(1e18),
@@ -35,5 +36,5 @@ def is_convertible(self, value: str) -> bool:
 
     def convert(self, value: str) -> int:
         value, unit = value.split(" ")
-
-        return int(Decimal(value) * ETHER_UNITS[unit.lower()])
+        converted_value = int(Decimal(value) * ETHER_UNITS[unit.lower()])
+        return CurrencyValue(converted_value)

tests/functional/conversion/test_ether.py

@@ -18,9 +18,12 @@
     unit=st.sampled_from(list(ETHER_UNITS.keys())),
 )
 def test_ether_conversions(value, unit, convert):
-    actual = convert(f"{value} {unit}", int)
+    currency_str = f"{value} {unit}"
+    actual = convert(currency_str, int)
     expected = int(value * ETHER_UNITS[unit])
     assert actual == expected
+    # Also show can compare directly with str.
+    assert actual == currency_str
 
 
 def test_bad_type(convert):

tests/functional/test_address.py

@@ -1,7 +1,7 @@
 import pytest
 from pydantic import BaseModel
 
-from ape.api.address import BaseAddress
+from ape.api.address import Address, BaseAddress
 from ape.types import AddressType
 
 
@@ -31,3 +31,12 @@ class CustomModel(BaseModel):
 
     model = CustomModel(address=zero_address)
     assert model.address == zero_address
+
+
+def test_balance(zero_address):
+    address = Address(zero_address)
+    actual = address.balance
+    expected = 0
+    assert actual == expected
+    # Also show can compare directly to currency-str.
+    assert actual == "0 ETH"