Add pytest-xdist support (#159)

- `launch_anvil()` will use a random port by default
- Run tests parallel

.github/workflows/test.yml

@@ -41,20 +41,24 @@ jobs:
       - name: Install dependencies
         run: |
           poetry env use '3.10'
-          poetry install -E data
+          poetry install --all-extras
       - name: Install Ganache
         run: yarn global add ganache
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
         with:
           version: 'nightly-e15e33a07c0920189fc336391f538c3dad53da73'
-      # - name: Workaround aave-v3-deploy npm ci failing randomly on Github
-      #   run: |
-      #     cd contracts/aave-v3-deploy
-      #     npm ci
+
+      # We also work around race condition for setting up Aave NPM packages.
+      - name: Setup aave for tests
+        run: |
+          poetry run install-aave-for-testing
+
+      # Run tests parallel.
+      # By default Github gives us only 2 CPUs, but we want to parallerise a bit more.
       - name: Run test scripts
         run: |
-          poetry run pytest --tb=native
+          poetry run pytest --tb=native -n 6 --dist loadscope
         env:
           BNB_CHAIN_JSON_RPC: ${{ secrets.BNB_CHAIN_JSON_RPC }}
           JSON_RPC_POLYGON_ARCHIVE: ${{ secrets.JSON_RPC_POLYGON_ARCHIVE }}

CHANGELOG.md

@@ -1,5 +1,8 @@
 # 0.22.17
 
+- Make testing and `launch_anvil` distrubuted safe by randomising Anvil localhost port it binds.
+  Test now run in few minutes instead of tens of minutes. Tests must be still run with
+  `pytest --dist loadscope` as individual test modules are not parallel safe.
 - Add ``eth_defi.broken_provider.set_block_tip_latency()`` to control the default delays 
   for which we expect the chain tip to stabilise.
 

docs/source/development.rst

@@ -92,6 +92,12 @@ Check that the tests of unmodified master branch pass:
 
      pytest
 
+For fast parallel test execution run with ``pytest-xdist`` across all of your CPUs:
+
+.. code-block::
+
+    pytest -n auto --dist loadscope
+
 You should get all green.
 
 Some tests will be skipped, because they require full EVM nodes. JSON-RPC needs to be configured through environment variables.

eth_defi/aave_v3/deployer.py

@@ -583,3 +583,17 @@ def get_aave_hardhard_export() -> dict:
     """
     hardhat_export_path = Path(__file__).resolve().parent / "aave-hardhat-localhost-export.json"
     return json.loads(hardhat_export_path.read_bytes())
+
+
+def install_aave_for_testing():
+    """Entry-point to ensure Aave dev env is installedon Github Actions.
+
+    Because pytest-xdist does not have very good support for preventing
+    race conditions with fixtures, we run this problematic test
+    before test suite.
+
+    It will do npm install for Aave deployer.
+    """
+    deployer = AaveDeployer()
+    deployer.install(echo=True)
+

eth_defi/provider/anvil.py

@@ -33,6 +33,7 @@
 """
 
 import logging
+import random
 import sys
 import time
 import warnings
@@ -46,7 +47,7 @@
 from requests.exceptions import ConnectionError as RequestsConnectionError
 from web3 import HTTPProvider, Web3
 
-from eth_defi.utils import is_localhost_port_listening, shutdown_hard
+from eth_defi.utils import is_localhost_port_listening, shutdown_hard, find_free_port
 
 logger = logging.getLogger(__name__)
 
@@ -192,7 +193,7 @@ def launch_anvil(
     fork_url: Optional[str] = None,
     unlocked_addresses: list[Union[HexAddress, str]] = None,
     cmd="anvil",
-    port: int = 19999,
+    port: int | tuple = (19999, 29999, 25),
     block_time=0,
     launch_wait_seconds=20.0,
     attempts=3,
@@ -313,7 +314,15 @@ def test_anvil_fork_transfer_busd(web3: Web3, large_busd_holder: HexAddress, use
         List of addresses of which ownership we take to allow test code to transact as them
 
     :param port:
-        Localhost port we bind for Anvil JSON-RPC
+        Localhost port we bind for Anvil JSON-RPC.
+
+        The tuple format is (min port, max port, opening attempts).
+
+        By default, takes a tuple range and tries to open a a random port in the range,
+        until empty found. This allows to run multiple parallel Anvil's during unit testing
+        with ``pytest -n auto``.
+
+        You can also specify an individual port.
 
     :param launch_wait_seconds:
         How long we wait anvil to start until giving up
@@ -354,10 +363,6 @@ def test_anvil_fork_transfer_busd(web3: Web3, large_busd_holder: HexAddress, use
 
     """
 
-    assert not is_localhost_port_listening(port), f"localhost port {port} occupied.\n" f"You might have a zombie Anvil process around.\nRun to kill: kill -SIGKILL $(lsof -ti:{port})"
-
-    url = f"http://localhost:{port}"
-
     attempts_left = attempts
     process = None
     final_cmd = None
@@ -367,6 +372,15 @@ def test_anvil_fork_transfer_busd(web3: Web3, large_busd_holder: HexAddress, use
     if unlocked_addresses is None:
         unlocked_addresses = []
 
+    # Find a free port
+    if type(port) == tuple:
+        port = find_free_port(*port)
+    else:
+        warnings.warn(f"launch_anvil(port={port}) called - we recommend using the default random port range instead", DeprecationWarning, stacklevel=2)
+        assert not is_localhost_port_listening(port), f"localhost port {port} occupied.\n" f"You might have a zombie Anvil process around.\nRun to kill: kill -SIGKILL $(lsof -ti:{port})"
+
+    url = f"http://localhost:{port}"
+
     # https://book.getfoundry.sh/reference/anvil/
     args = dict(
         port=port,

eth_defi/utils.py

@@ -2,6 +2,7 @@
 import calendar
 import datetime
 import logging
+import random
 import socket
 import time
 from typing import Optional, Tuple
@@ -37,6 +38,41 @@ def is_localhost_port_listening(port: int, host="localhost") -> bool:
     return result_of_check == 0
 
 
+def find_free_port(min_port: int, max_port: int, max_attempt: int) -> int:
+    """Find a free localhost port to bind.
+
+    Does by random.
+
+    .. note ::
+
+        Subject to race condition, but should be rareish.
+
+    :param min_port:
+        Minimum port range
+
+    :param max_port:
+        Maximum port range
+
+    :param max_attempt:
+        Give up and die with an exception if no port found after this many attempts.
+
+    :return:
+        Free port number
+    """
+
+    assert type(min_port) == int
+    assert type(max_port) == int
+    assert type(max_attempt) == int
+
+    for attempt in range(0, max_attempt):
+        random_port = random.randrange(start=min_port, stop=max_port)
+        logger.info("Attempting to allocate port %d to Anvil", random_port)
+        if not is_localhost_port_listening(random_port, "127.0.0.1"):
+            return random_port
+
+    raise RuntimeError(f"Could not open a port with a spec: {min_port} - {max_port}, {max_attempt} attemps")
+
+
 def shutdown_hard(
     process: psutil.Popen,
     log_level: Optional[int] = None,