feat(base_types): Add Wei type (ethereum#825)

* feat(base_types): Add Wei

* docs: changelog

* Apply suggestions from code review

Co-authored-by: danceratopz <[email protected]>

* fix(base_types): tox

---------

Co-authored-by: danceratopz <[email protected]>

docs/CHANGELOG.md

@@ -41,6 +41,7 @@ Test fixtures for use by clients are available for each release on the [Github r
 - 🐞 Fix erroneous fork message in pytest session header with development forks ([#806](https://github.com/ethereum/execution-spec-tests/pull/806)).
 - 🐞 Fix `Conditional` code generator in EOF mode ([#821](https://github.com/ethereum/execution-spec-tests/pull/821))
 - 🔀 `ethereum_test_rpc` library has been created with what was previously `ethereum_test_tools.rpc` ([#822](https://github.com/ethereum/execution-spec-tests/pull/822))
+- ✨ Add `Wei` type to `ethereum_test_base_types` which allows parsing wei amounts from strings like "1 ether", "1000 wei", "10**2 gwei", etc ([#825](https://github.com/ethereum/execution-spec-tests/pull/825))
 
 ### 🔧 EVM Tools
 

src/ethereum_test_base_types/__init__.py

@@ -15,6 +15,7 @@
     HexNumber,
     Number,
     NumberBoundTypeVar,
+    Wei,
     ZeroPaddedHexNumber,
 )
 from .composite_types import Account, Alloc, Storage, StorageRootType
@@ -60,6 +61,7 @@
     "TestAddress2",
     "TestPrivateKey",
     "TestPrivateKey2",
+    "Wei",
     "ZeroPaddedHexNumber",
     "to_bytes",
     "to_hex",

src/ethereum_test_base_types/base_types.py

@@ -75,6 +75,56 @@ def or_none(cls: Type[N], input: N | NumberConvertible | None) -> N | None:
         return cls(input)
 
 
+class Wei(Number):
+    """
+    Class that helps represent wei that can be parsed from strings
+    """
+
+    def __new__(cls, input: NumberConvertible | N):
+        """
+        Creates a new Number object.
+        """
+        if isinstance(input, str):
+            words = input.split()
+            multiplier = 1
+            assert len(words) <= 2
+            value_str = words[0]
+            if len(words) > 1:
+                unit = words[1].lower()
+                multiplier = cls._get_multiplier(unit)
+            value: float
+            if "**" in value_str:
+                base, exp = value_str.split("**")
+                value = float(base) ** int(exp)
+            else:
+                value = float(value_str)
+            return super(Number, cls).__new__(cls, value * multiplier)
+        return super(Number, cls).__new__(cls, to_number(input))
+
+    @staticmethod
+    def _get_multiplier(unit: str) -> int:
+        """
+        Returns the multiplier for the given unit of wei, handling synonyms.
+        """
+        match unit:
+            case "wei":
+                return 1
+            case "kwei" | "babbage" | "femtoether":
+                return 10**3
+            case "mwei" | "lovelace" | "picoether":
+                return 10**6
+            case "gwei" | "shannon" | "nanoether" | "nano":
+                return 10**9
+            case "szabo" | "microether" | "micro":
+                return 10**12
+            case "finney" | "milliether" | "milli":
+                return 10**15
+            case "ether":
+                return 10**18
+            case _:
+                raise ValueError(f"Invalid unit {unit}")
+
+
 class HexNumber(Number):
     """
     Class that helps represent an hexadecimal numbers in tests.

src/ethereum_test_base_types/tests/test_base_types.py

@@ -6,7 +6,7 @@
 
 import pytest
 
-from ..base_types import Address, Hash
+from ..base_types import Address, Hash, Wei
 
 
 @pytest.mark.parametrize(
@@ -52,3 +52,42 @@ def test_comparisons(a: Any, b: Any, equal: bool):
     else:
         assert a != b
         assert not a == b
+
+
+@pytest.mark.parametrize(
+    "s, expected",
+    [
+        ("0", 0),
+        ("10**18", 10**18),
+        ("1e18", 10**18),
+        ("1 ether", 10**18),
+        ("2 ether", 2 * 10**18),
+        ("2.1 ether", 2.1 * 10**18),
+        ("2.1 Ether", 2.1 * 10**18),
+        ("2.1 ETHER", 2.1 * 10**18),
+        ("1 wei", 1),
+        ("10**9 wei", 10**9),
+        ("1 gwei", 10**9),
+        ("1 szabo", 10**12),
+        ("1 finney", 10**15),
+        ("1 kwei", 10**3),
+        ("1 mwei", 10**6),
+        ("1 babbage", 10**3),
+        ("1 femtoether", 10**3),
+        ("1 Lovelace", 10**6),
+        ("1 Picoether", 10**6),
+        ("1 gwei", 10**9),
+        ("1 shannon", 10**9),
+        ("1 nanoether", 10**9),
+        ("1 nano", 10**9),
+        ("1 microether", 10**12),
+        ("1 micro", 10**12),
+        ("1 milliether", 10**15),
+        ("1 milli", 10**15),
+    ],
+)
+def test_wei_parsing(s: str, expected: int):
+    """
+    Test the parsing of wei values.
+    """
+    assert Wei(s) == expected