Package: platon-tester
Platon TesterTools for testing platon based applications.Installationpipinstallplaton-testerQuick Start>>>fromplaton_testerimportPlatonTester>>>t=PlatonTester()>>>t.get_accounts()('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','0x7d577a597B2742b498Cb5Cf0C26cDCD726d39E6e','0xDCEceAF3fc5C0a63d195d69b1A90011B7B19650D','0x598443F1880Ef585B21f1d7585Bd0577402861E5','0x13cBB8D99C6C4e0f2728C7d72606e78A29C4E224','0x77dB2BEBBA79Db42a978F896968f4afCE746ea1F','0x24143873e0E0815fdCBcfFDbe09C979CbF9Ad013','0x10A1c1CB95c92EC31D3f22C66Eef1d9f3F258c6B','0xe0FC04FA2d34a66B779fd5CEe748268032a146c0','0x90F0B1EBbbA1C1936aFF7AAf20a7878FF9e04B6c')>>>t.get_balance('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1')1000000000000000000000000>>>t.send_transaction({'from':'0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','to':'0x7d577a597B2742b498Cb5Cf0C26cDCD726d39E6e','gas':21000,'value':1})'0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25'>>>t.get_transaction_by_hash('0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25'){'block_hash':'0x89c03ecb6bbf3ff533b04a663fa98d59c9d985de806d1a9dcafaad7c993ee6e8','block_number':0,'data':'0x','from':'0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','gas':21000,'gas_price':1,'hash':'0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25','nonce':0,'r':114833774457827084417823702749930473879683934597320921824765632039428214735160,'s':52192522150044217242428968890330558187037131043598164958282684822175843828481,'to':'0x7d577a597B2742b498Cb5Cf0C26cDCD726d39E6e','transaction_index':0,'v':27,'value':1}>>>t.get_transaction_receipt('0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25'){'block_hash':'0x89c03ecb6bbf3ff533b04a663fa98d59c9d985de806d1a9dcafaad7c993ee6e8','block_number':0,'contract_address':None,'cumulative_gas_used':21000,'gas_used':21000,'logs':(),'transaction_hash':'0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25','transaction_index':0}Developmentpipinstall-e".[dev]"Running the testsYou can run the tests with:py.testtestsOr you can installtoxto run the full test suite.ReleasingPandoc is required for transforming the markdown README to the proper format to
render correctly on pypi.For Debian-like systems:apt install pandocOr on OSX:brewinstallpandocTo release a new version:bumpversion$$VERSION_PART_TO_BUMP$$gitpush&&gitpush--tags
makereleaseHow to bumpversionThe version format for this repo is{major}.{minor}.{patch}for stable, and{major}.{minor}.{patch}-{stage}.{devnum}for unstable (stagecan be alpha or beta).To issue the next version in line, use bumpversion and specify which part to bump,
likebumpversion minororbumpversion devnum.If you are in a beta version,bumpversion stagewill switch to a stable.To issue an unstable version when the current version is stable, specify the
new version explicitly, likebumpversion --new-version 4.0.0-alpha.1 devnumDocumentationInput and output data formatsThe platon tester library strictly enforces the following input formats and
types.Hexidecimal valuesmustbe text (not byte) strings.  The0xprefix is optional.Any address which contains mixed-case alpha characters will be validated as a checksummed address as specified byEIP-5532-byte hashesmustbe hexidecimal encoded.Numeric valuesmustbe in their integer representation.Similarly, platon tester ensures that return values conform to similar rules.32-byte hashes will be returned in their hexidecimal encoded representation.Addresses will be returned in their hexidecimal representation and EIP55 checksummed.Numeric values will be returned as integers.Block NumbersAnyblock_numberparameter will accept the following string values.'latest': for the latest mined block.'pending': for the current un-mined block.'earliest': for the genesis block.Note: Thesemustbe text strings (not byte stringS)platon_tester.PlatonTesterAPIInstantiationplaton_tester.PlatonTester(backend=None, validator=None, normalizer=None, auto_mine_transactions=True, fork_blocks=None)ThePlatonTesterobject is the sole API entrypoint.  Instantiation of this
object accepts the following parameters.backend: The chain backend being used.  See thechain backendsvalidator: The validator to used.  See thevalidatorsnormalizer: The normalizer to used.  See thenormalizersauto_mine_transactions: Iftruthytransactions will be automatically mined at the time they are submitted.  Seeenable_auto_mine_transactionsanddisable_auto_mine_transactions.fork_blocks: configures which block numbers the various network hard fork rules will be activated.  Seefork-rules>>>fromplaton_testerimportPlatonTester>>>t=PlatonTester()>>>t<platon_tester.main.PlatonTesterat0x102255710>Fork RulesPlaton tester uses the Byzantium rules, starting at block 0.Time TravelThe chain can only time travel forward in time.PlatonTester.time_travel(timestamp)Thetimestampmust be an integer, strictly greater than the current timestamp
of the latest block.Note: Time traveling will result in a new block being mined.MiningManually mining blocks can be done with the following API.  Thecoinbaseparameter of these methodsmustbe a hexidecimal encoded address.PlatonTester.mine_blocks(num_blocks=1, coinbase=None)Minesnum_blocksnew blocks, returning an iterable of the newly mined block hashes.PlatonTester.mine_block(coinbase=None)Mines a single new block, returning the mined block's hash.Auto-mining transactionsBy default all transactions are mined immediately.  This means that each transaction you send will result in a new block being mined, and that all blocks will only ever have at most a single transaction.  This behavior can be controlled with the following methods.PlatonTester.enable_auto_mine_transactions()Turns on auto-mining of transactions.PlatonTester.disable_auto_mine_transactions()Turnsoffauto-mining of transactions.AccountsThe following API can be used to interact with account data.  Theaccountparameter in these methodsmustbe a hexidecimal encode address.PlatonTester.get_accounts()Returns an iterable of the accounts that the tester knows about.  All accounts
in this list will be EIP55 checksummed.>>>t.get_accounts()('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','0x7d577a597B2742b498Cb5Cf0C26cDCD726d39E6e',...'0x90F0B1EBbbA1C1936aFF7AAf20a7878FF9e04B6c')PlatonTester.add_account(private_key, password=None)Adds a new account for the given private key.  Returns the hex encoded address
of the added account.>>>t.add_account('0x58d23b55bc9cdce1f18c2500f40ff4ab7245df9a89505e9b1fa4851f623d241d')'0xdc544d1aa88ff8bbd2f2aec754b1f1e99e1812fd'By default, added accounts are unlocked and do not have a password.  If you
would like to add an account which has a password, you can supply the password
as the second parameter.>>>t.add_account('0x58d23b55bc9cdce1f18c2500f40ff4ab7245df9a89505e9b1fa4851f623d241d','my-secret')'0xdc544d1aa88ff8bbd2f2aec754b1f1e99e1812fd'PlatonTester.unlock_account(account, password, unlock_seconds=None)Unlocks the given account if the provided password matches.Raises aValidationErrorif:The account is not known.The password does not match.The account was created without a password.>>>t.unlock_account('0xdc544d1aa88ff8bbd2f2aec754b1f1e99e1812fd','my-secret')By default, accounts will be unlocked indefinitely.  You can however unlock an
account for a specified amount of time by providing the desired duration in
seconds.# unlock for 1 hour.>>>t.unlock_account('0xdc544d1aa88ff8bbd2f2aec754b1f1e99e1812fd','my-secret',60*60)PlatonTester.lock_account(account)Locks the provide account.Raises aValidationErrorif:The account is not knownThe account does not have a password.PlatonTester.get_balance(account) -> integerReturns the balance, in wei, for the provided account.>>>t.get_balance('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1')1000004999999999999999999PlatonTester.get_nonce(account) -> integerReturns the nonce for the provided account.>>>t.get_nonce('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1')1PlatonTester.get_code(account) -> hex stringReturns the code for the given account.>>>t.get_code('0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1')"0x"Blocks, Transactions, and ReceiptsPlatonTester.get_transaction_by_hash(transaction_hash) -> transaction-objectReturns the transaction for the given hash, raising aTransactionNotFoundexception if the
transaction cannot be found.>>>t.get_transaction_by_hash('0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25'){'block_hash':'0x89c03ecb6bbf3ff533b04a663fa98d59c9d985de806d1a9dcafaad7c993ee6e8','block_number':0,'hash':'0x140c1da1370a908e4c0f7c6e33bb97182011707c6a9aff954bef1084c8a48b25','transaction_index':0,'from':'0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','to':'0x7d577a597B2742b498Cb5Cf0C26cDCD726d39E6e','value':1,'gas':21000,'gas_price':1,'nonce':0,'data':'0x','v':27,'r':114833774457827084417823702749930473879683934597320921824765632039428214735160,'s':52192522150044217242428968890330558187037131043598164958282684822175843828481}Note: For unmined transaction,transaction_index,block_numberandblock_hashwill all beNone.PlatonTester.get_block_by_number(block_number, full_transactions=False) -> block-objectReturns the block for the givenblock_number.  Seeblock
numbersfor named block numbers you can use.  Iffull_transactionsis truthy, then the transactions array will be populated
with full transaction objects as opposed to their hashes.RaisesBlockNotFoundif a block for the given number
cannot be found.>>>t.get_block_by_number(1){'difficulty':131072,'extra_data':'0x0000000000000000000000000000000000000000000000000000000000000000','gas_limit':999023468,'gas_used':0,'hash':'0x0f50c8ea0f67ce0b7bff51ae866159edc443bde87de2ab26010a15b777244ddd','logs_bloom':0,'miner':'0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','nonce':'0x0000000000000000','number':1,'parent_hash':'0x89c03ecb6bbf3ff533b04a663fa98d59c9d985de806d1a9dcafaad7c993ee6e8','sha3_uncles':'0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347','size':472,'state_root':'0xbd92123803c9e71018617ce3dc6cbbdf130973bdbd0e14ff340c57c8a835b74b','timestamp':1410973360,'total_difficulty':262144,'transactions':(),'transactions_root':'0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421','uncles':()}PlatonTester.get_block_by_hash(block_hash, full_transactions=True) -> block-objectReturns the block for the givenblock_hash.  Thefull_transactionsparameter behaves the same as inget_block_by_number.RaisesBlockNotFoundif a block for the given hash
cannot be found.>>>t.get_block_by_hash('0x0f50c8ea0f67ce0b7bff51ae866159edc443bde87de2ab26010a15b777244ddd'){'difficulty':131072,'extra_data':'0x0000000000000000000000000000000000000000000000000000000000000000','gas_limit':999023468,'gas_used':0,'hash':'0x0f50c8ea0f67ce0b7bff51ae866159edc443bde87de2ab26010a15b777244ddd','logs_bloom':0,'miner':'0x82A978B3f5962A5b0957d9ee9eEf472EE55B42F1','nonce':'0x0000000000000000','number':1,'parent_hash':'0x89c03ecb6bbf3ff533b04a663fa98d59c9d985de806d1a9dcafaad7c993ee6e8','sha3_uncles':'0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347','size':472,'state_root':'0xbd92123803c9e71018617ce3dc6cbbdf130973bdbd0e14ff340c57c8a835b74b','timestamp':1410973360,'total_difficulty':262144,'transactions':(),'transactions_root':'0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421','uncles':()}PlatonTester.get_transaction_receipt(transaction_hash)Returns the receipt for the giventransaction_hash, raisingTransactionNotFoundif no transaction can be
found for the given hash.>>>t.get_transaction_receipt('0x9a7cc8b7accf54ecb1901bf4d0178f28ca457bb9f9c245692c0ca8fabef08d3b'){'block_hash':'0x878f779d8bb25b25fb78fc16b8d64d70a5961310ef1689571aec632e9424290c','block_number':2,'contract_address':None,'cumulative_gas_used':23154,'gas_used':23154,'logs':({'address':'0xd6F084Ee15E38c4f7e091f8DD0FE6Fe4a0E203Ef','block_hash':'0x878f779d8bb25b25fb78fc16b8d64d70a5961310ef1689571aec632e9424290c','block_number':2,'data':'0x','log_index':0,'topics':('0xf70fe689e290d8ce2b2a388ac28db36fbb0e16a6d89c6804c461f65a1b40bb15','0x0000000000000000000000000000000000000000000000000000000000003039'),'transaction_hash':'0x9a7cc8b7accf54ecb1901bf4d0178f28ca457bb9f9c245692c0ca8fabef08d3b','transaction_index':0,'type':'mined'},),'transaction_hash':'0x9a7cc8b7accf54ecb1901bf4d0178f28ca457bb9f9c245692c0ca8fabef08d3b','transaction_index':0}Receipts for unmined transactions will have all ofblock_hash,block_numberandtransaction_indexset toNone.Receipts for transactions which create a contract will have the created contract address in thecontract_addressfield.Transaction SendingA transaction is a formatted as a dictionary with the following keys and
values.from: The address of the account sending the transaction (hexidecimal string).to: The address of the account the transaction is being sent to.  Empty string should be used to trigger contract creation (hexidecimal string).gas: Sets the gas limit for transaction execution (integer).gas_price: Sets the price per unit of gas in wei that will be paid for transaction execution (integer).value: The amount of ether in wei that should be sent with the transaction (integer).data: The data for the transaction (hexidecimal string).MethodsPlatonTester.send_transaction(transaction) -> transaction_hashSends the providedtransactionobject, returning thetransaction_hashfor
the sent transaction.PlatonTester.call(transaction, block_number='latest')Executes the providedtransactionobject at the evm state from the block
denoted by theblock_numberparameter, returning the resulting bytes return
value from the evm.PlatonTester.estimate_gas(transaction)Executes the providedtransactionobject, measuring and returning the gas
consumption.Logs and FiltersPlatonTester.create_block_filter() -> integerCreates a new filter for newly mined blocks.  Returns thefilter_idwhich can
be used to retrieve the block hashes for the mined blocks.>>>filter_id=t.create_block_filter()>>>filter_id=t.create_block_filter()>>>t.mine_blocks(3)>>>t.get_only_filter_changes(filter_id)('0x07004287f82c1a7ab15d7b8baa03ac14d7e9167ab74e47e1dc4bd2213dd18431','0x5e3222c506585e1202da08c7231afdc5e472c777c245b822f44f141d335c744a','0x4051c3ba3dcca95da5db1be38e44f5b47fd1a855ba522123e3254fe3f8e271ea')>>>t.mine_blocks(2)>>>t.get_only_filter_changes(filter_id)('0x6649c3a7cb3c7ede3a4fd10ae9dd63775eccdafe39ace5f5a9ae81d360089fba','0x04890a08bca0ed2f1496eb29c5dc7aa66014c85377c6d9d9c2c315f85204b39c')>>>t.get_all_filter_logs(filter_id)('0x07004287f82c1a7ab15d7b8baa03ac14d7e9167ab74e47e1dc4bd2213dd18431','0x5e3222c506585e1202da08c7231afdc5e472c777c245b822f44f141d335c744a','0x4051c3ba3dcca95da5db1be38e44f5b47fd1a855ba522123e3254fe3f8e271ea','0x6649c3a7cb3c7ede3a4fd10ae9dd63775eccdafe39ace5f5a9ae81d360089fba','0x04890a08bca0ed2f1496eb29c5dc7aa66014c85377c6d9d9c2c315f85204b39c')PlatonTester.create_pending_transaction_filter() -> integerCreates a new filter for pending transactions.  Returns thefilter_idwhich
can be used to retrieve the transaction hashes for the pending transactions.>>>filter_id=t.create_pending_transaction_filter()>>>t.send_transaction({...})'0x07f20bf9586e373ac914a40e99119c4932bee343d89ba852ccfc9af1fd541566'>>>t.send_transaction({...})'0xff85f7751d132b66c03e548e736f870797b0f24f3ed41dfe5fc628eb2cbc3505'>>>t.get_only_filter_changes(filter_id)('0x07f20bf9586e373ac914a40e99119c4932bee343d89ba852ccfc9af1fd541566','0xff85f7751d132b66c03e548e736f870797b0f24f3ed41dfe5fc628eb2cbc3505')>>>t.send_transaction({...})'0xb07801f7e8b1cfa52b64271fa2673c4b8d64cc21cdbc5fde51d5858c94c2d26a'>>>t.get_only_filter_changes(filter_id)('0xb07801f7e8b1cfa52b64271fa2673c4b8d64cc21cdbc5fde51d5858c94c2d26a',)>>>t.get_all_filter_logs(filter_id)('0x07f20bf9586e373ac914a40e99119c4932bee343d89ba852ccfc9af1fd541566','0xff85f7751d132b66c03e548e736f870797b0f24f3ed41dfe5fc628eb2cbc3505','0xb07801f7e8b1cfa52b64271fa2673c4b8d64cc21cdbc5fde51d5858c94c2d26a')PlatonTester.create_log_filter(from_block=None, to_block=None, address=None, topics=None) -> integerCreates a new filter for logs produced by transactions.  The parameters for
this function can be used to filter the log entries.>>>filter_id=t.create_log_filter()>>>t.send_transaction({...})# something that produces a log entry'0x728bf75fc7d23845f328d2223df7fe9cafc6e7d23792457b625d5b60d2b22b7c'>>>t.send_transaction({...})# something that produces a log entry'0x63f5b381ffd09940ce22c45a3f4e163bd743851cb6b4f43771fbf0b3c14b2f8a'>>>t.get_only_filter_changes(filter_id)({'address':'0xd6F084Ee15E38c4f7e091f8DD0FE6Fe4a0E203Ef','block_hash':'0x68c0f318388003b652eae334efbed8bd345c469bd0ca77469183fc9693c23e13','block_number':11,'data':'0x','log_index':0,'topics':('0xf70fe689e290d8ce2b2a388ac28db36fbb0e16a6d89c6804c461f65a1b40bb15','0x0000000000000000000000000000000000000000000000000000000000003039'),'transaction_hash':'0x728bf75fc7d23845f328d2223df7fe9cafc6e7d23792457b625d5b60d2b22b7c','transaction_index':0,'type':'mined'},{'address':'0xd6F084Ee15E38c4f7e091f8DD0FE6Fe4a0E203Ef','block_hash':'0x07d7e46be6f9ba53ecd4323fb99ec656e652c4b14f4b8e8a244ee7f997464725','block_number':12,'data':'0x','log_index':0,'topics':('0xf70fe689e290d8ce2b2a388ac28db36fbb0e16a6d89c6804c461f65a1b40bb15','0x0000000000000000000000000000000000000000000000000000000000010932'),'transaction_hash':'0x63f5b381ffd09940ce22c45a3f4e163bd743851cb6b4f43771fbf0b3c14b2f8a','transaction_index':0,'type':'mined'})Seethe filtering guidefor detailed information on how to use filters.PlatonTester.delete_filter(filter_id)Removes the filter for the providefilter_id.  If no filter is found for the
givenfilter_id, raisesFilterNotFound.PlatonTester.get_only_filter_changes(filter_id) -> transaction_hash or block_hash or log_entryReturns all new values for the providedfilter_idthat have not previously
been returned through this API.  RaisesFilterNotFoundif no filter is found for the givenfilter_id.PlatonTester.get_all_filter_logs(filter_id) -> transaction_hash or block_hash or log_entryReturns all values for the providedfilter_id. RaisesFilterNotFoundif no filter is found for the givenfilter_id.Snapshots and ResettingPlatonTester.take_snapshot() -> snapshot_idTakes a snapshot of the current chain state and returns the snapshot id.PlatonTester.revert_to_snapshot(snapshot_id)Reverts the chain to the chain state associated with the givensnapshot_id.
RaisesSnapshotNotFoundif no snapshot is know
for the given id.Errors and Exceptionsplaton_tester.exceptions.TransactionNotFoundRaised in cases where a transaction cannot be found for the provided transaction hash.platon_tester.exceptions.BlockNotFoundRaised in cases where a block cannot be found for either a provided number or
hash.platon_tester.exceptions.FilterNotFoundRaised in cases where a filter cannot be found for the provided filter id.platon_tester.exceptions.SnapshotNotFoundRaised in cases where a snapshot cannot be found for the provided snapshot id.BackendsPlaton tester is written using a pluggable backend system.Backend DependenciesPlaton tester does not install any of the dependencies needed to use the
various backends by default.  You can however install platon tester with the
necessary dependencies using the following method.$pipinstallplaton-tester[<backend-name>]You should replace<backend-name>with the name of the desired testing
backend.  Available backends are:py-evm:PyEVM (alpha)(experimental)Selecting a BackendYou can select which backend in a few different ways.The most direct way is to manually pass in the backend instance you wish to
use.>>>fromplaton_testerimportPlatonTester,MockBackend>>>t=PlatonTester(backend=MockBackend())Platon tester also supports configuration using the environment variablePLATON_TESTER_CHAIN_BACKEND.  This should be set to the import path for the
backend class you wish to use.Available BackendsPlaton tester can be used with the following backends.PyEVM (experimental)MockBackendMockBackendThis backend has limited functionality.  It cannot perform any VM computations.
It mocks out all of the objects and interactions.>>>fromplaton_testerimportPlatonTester,MockBackend>>>t=PlatonTester(MockBackend())PyEVM (experimental)WARNINGPy-EVM is experimental and should not be relied on for mission critical testing at this stage.Uses the experimental Py-EVM library.>>>fromplaton_testerimportPlatonTester,PyEVMBackend>>>t=PlatonTester(PyEVMBackend())PyEVM Genesis Parameters and StateIf you need to specify custom genesis parameters and state, you can build your own parametersdictto use instead of the default
when initializing a backend.  Only default values can be overridden or aValueErrorwill be raised.# Default Genesis Parameters

default_genesis_params = {
    "bloom": 0,
    "coinbase": GENESIS_COINBASE,
    "difficulty": GENESIS_DIFFICULTY,
    "extra_data": GENESIS_EXTRA_DATA,
    "gas_limit": GENESIS_GAS_LIMIT,
    "gas_used": 0,
    "mix_hash": GENESIS_MIX_HASH,
    "nonce": GENESIS_NONCE,
    "block_number": GENESIS_BLOCK_NUMBER,
    "parent_hash": GENESIS_PARENT_HASH,
    "receipt_root": BLANK_ROOT_HASH,
    "timestamp": int(time.time()),
    "transaction_root": BLANK_ROOT_HASH,
    "uncles_hash": EMPTY_RLP_LIST_HASH
}To generate a genesis parametersdictwith an overridden parameters, pass agenesis_overridesdicttoPyEVM.generate_genesis_params.>>>fromplaton_testerimportPyEVMBackend,PlatonTester>>>genesis_overrides={'gas_limit':4500000}>>>custom_genesis_params=PyEVMBackend._generate_genesis_params(overrides=genesis_overrides)# Generates the following `dict`:# custom_genesis_params = {#     "bloom": 0,#     "coinbase": GENESIS_COINBASE,#     "difficulty": GENESIS_DIFFICULTY,#     "extra_data": GENESIS_EXTRA_DATA,#     "gas_limit": 4500000    # <<< Overidden Value <<<#     "gas_used": 0,#     "mix_hash": GENESIS_MIX_HASH,#     "nonce": GENESIS_NONCE,#     "block_number": GENESIS_BLOCK_NUMBER,#     "parent_hash": GENESIS_PARENT_HASH,#     "receipt_root": BLANK_ROOT_HASH,#     "timestamp": int(time.time()),#     "transaction_root": BLANK_ROOT_HASH,#     "uncles_hash": EMPTY_RLP_LIST_HASH# }Then pass the generatedcustom_genesis_paramsdictto the backend's__init__>>>fromplaton_testerimportPyEVMBackend,PlatonTester>>>pyevm_backend=PyEVMBackend(genesis_parameters=custom_genesis_params)>>>t=PlatonTester(backend=pyevm_backend)Overriding genesis state is similar to overriding genesis state, but requires the consideration of test accounts.
To override the genesis state of accounts, pass astate_overridesdicttoPyEVM.generate_genesis_state,
and optionally, the number of accounts to create.NOTE: The same state is applied to all generated test accounts.# Default Account Genesis State

default_account_state = {
    'balance': to_von(1000000, 'ether'),
    'storage': {},
    'code': b'',
    'nonce': 0,
}For Example, to create 3 test accounts, each with a balance of 100 ETH each:>>>fromplaton_testerimportPlatonTester,PyEVMBackend>>>fromplaton_utilsimportto_von>>>state_overrides={'balance':to_von(100,'ether')}>>>custom_genesis_state=PyEVMBackend._generate_genesis_state(overrides=state_overrides,num_accounts=3)# Then pass the generated `custom_genesis_state` `dict` to the backend's `__init__`>>>pyevm_backend=PyEVMBackend(genesis_state=custom_genesis_state)>>>t=PlatonTester(backend=pyevm_backend)Implementing Custom BackendsThe base classplaton_tester.backends.base.BaseChainBackendis the recommended
base class to begin with if you wish to write your own backend.Details on implementation are beyond the scope of this document.Data FormatsPlaton tester uses two formats for data.Thenormalformat is the data format the is expected as input arguments to allPlatonTestermethods as well as the return types from all method calls.Thecanonicalformat is the data format that is used internally by the backend class.Platon tester enforces strict validation rules on these formats.Canonical FormatsThe canonical format is intended for low level handling by backends.32 byte hashes:bytesof length 32Arbitrary length strings:bytesAddresses:bytesof length 20Integers:intArray Types:tupleNormal FormatsThe normal format is intended for use by end users.32 byte hashes:0xprefixed hexidecimal encoded text strings (not byte strings)Arbitrary length strings:0xprefixed hexidecimal encoded text strings (not byte strings)Addresses:0xprefixed and EIP55 checksummed hexidecimal encoded text strings (not byte strings)Integers:intArray Types:tupleNormalization and ValidationBeware! Here there be dragons...  This section of the documentation is only
relevant if you intend to build tooling on top of this library.The platon tester provides strong guarantees that backends can be swapped out
seamlessly without effecting the data formats of both the input arguments and
return values.  This is accomplished using a two step process of strictnormalizationandvalidation.All inputs to the methods of thePlatonTesterare first validated then
normalized to acanonicalformat.  Return values are put through this process
as well, first validating the data returned by the backend, and then
normalizing it from thecanonicalformat to thenormalform before being
returned.NormalizationThePlatonTesterdelegates normalization to whatevernormalizerwas
passed in during instantiation.  If no value was provided, the default
normalizer will be used fromplaton_tester.normalization.default.DefaultNormalizer.The specifics of this object are beyong the scope of this document.ValidationThePlatonTesterdelegates validation to whatevervalidatorwas
passed in during instantiation.  If no value was provided, the default
validator will be used fromplaton_tester.validation.default.DefaultValidator.The specifics of this object are beyong the scope of this document.Use with Web3.pySee theweb3.py documentationfor
information on thePlatonTesterprovider which integrates with this
library.