def get_chain_backend_class(backend_import_path=None):
warnings.simplefilter('default')
if backend_import_path is None:
if 'ETHEREUM_TESTER_CHAIN_BACKEND' in os.environ:
backend_import_path = os.environ['ETHEREUM_TESTER_CHAIN_BACKEND']
elif is_pyevm_available():
vi = sys.version_info
if vi.major != 3 or vi.minor < 5:
warnings.warn(
UserWarning("Py-EVM does not support python < 3.5"))
backend_import_path = get_import_path(PyEVMBackend)
elif is_pyethereum21_available():
vi = sys.version_info
if vi.major != 3 or vi.minor < 5:
warnings.warn(
UserWarning(
"PyEthereum 2.1.0+ does not support python < 3.5"))
backend_import_path = get_import_path(PyEthereum21Backend)
elif is_pyethereum16_available():
backend_import_path = get_import_path(PyEthereum16Backend)
else:
warnings.warn(
UserWarning(
"Ethereum Tester: No backend was explicitely set, and no *full* "
"backends were available. Falling back to the `MockBackend` "
"which does not support all EVM functionality. Please refer to "
"the `eth-tester` documentation for information on what "
"backends are available and how to set them."))
backend_import_path = get_import_path(MockBackend)
return import_string(backend_import_path)
from __future__ import absolute_import
import os
from eth_tester.utils.module_loading import (
get_import_path,
import_string,
)
from .default import (
DefaultNormalizer, )
DEFAULT_NORMALIZER_CLASS = get_import_path(DefaultNormalizer)
def get_normalizer_backend_class(backend_import_path=None):
if backend_import_path is None:
backend_import_path = os.environ.get(
'ETHEREUM_TESTER_NORMALIZER_BACKEND',
DEFAULT_NORMALIZER_CLASS,
)
return import_string(backend_import_path)
def get_normalizer_backend(backend_class=None):
if backend_class is None:
backend_class = get_normalizer_backend_class()
return backend_class()