Add AlternateChainSpecs class

package/test_tools/__init__.py

@@ -13,6 +13,7 @@ from test_tools.__private import (
     paths_to_executables,
 )
 from test_tools.__private.account import Account, PrivateKey, PublicKey
+from test_tools.__private.alternate_chain_specs import AlternateChainSpecs, HardforkSchedule, InitialVesting
 from test_tools.__private.block_log import BlockLog
 
 # User handles
@@ -48,6 +49,9 @@ __all__ = [
     "Asset",
     "Time",
     "TimeFormats",
+    "AlternateChainSpecs",
+    "HardforkSchedule",
+    "InitialVesting",
 ]
 
 if TYPE_CHECKING:

package/test_tools/__private/alternate_chain_specs.py

+from __future__ import annotations
+
+from pathlib import Path
+from typing import ClassVar
+
+from pydantic import BaseModel, Protocol
+
+from test_tools.__private.user_handles import context
+
+
+class InitialVesting(BaseModel):
+    vests_per_hive: int
+    hive_amount: int
+
+
+class HardforkSchedule(BaseModel):
+    hardfork: int
+    block_num: int
+
+
+class AlternateChainSpecs(BaseModel):
+    FILENAME: ClassVar[str] = "alternate-chain-spec.json"
+
+    genesis_time: int
+    hardfork_schedule: list[HardforkSchedule]
+    init_supply: int | None = None
+    hbd_init_supply: int | None = None
+    initial_vesting: InitialVesting | None = None
+    init_witnesses: list[str] | None = None
+    hive_owner_update_limit: int | None = None
+
+    def export_to_file(self, output_dir: Path | None = None) -> Path:
+        if output_dir is None:
+            output_dir = context.get_current_directory()
+        output_dir.mkdir(parents=True, exist_ok=True)
+        destination = output_dir / AlternateChainSpecs.FILENAME
+        with destination.open("w") as json_file:
+            json_file.write(self.json(exclude_none=True))
+        return destination
+
+    @classmethod
+    def parse_file(
+        cls: type[AlternateChainSpecs],
+        path: str | Path,
+        *,
+        content_type: str | None = None,
+        encoding: str = "utf8",
+        proto: Protocol | None = None,
+        allow_pickle: bool = False,
+    ) -> AlternateChainSpecs:
+        if isinstance(path, str):
+            path = Path(path)
+
+        if path.is_dir():
+            path = path / AlternateChainSpecs.FILENAME
+
+        assert path.is_file(), f"Given path: `{path.as_posix()}` is not pointing to file!"
+        return super().parse_file(
+            path, content_type=content_type, encoding=encoding, proto=proto, allow_pickle=allow_pickle  # type: ignore
+        )