Allow block identifier for Contract.estimateGas

docs/contracts.rst

@@ -822,7 +822,7 @@ Methods
         # You can check the state after your pending transactions (if supported by your node):
         >>> token_contract.functions.myBalance().call(block_identifier='pending')
 
-.. py:method:: ContractFunction.estimateGas(transaction)
+.. py:method:: ContractFunction.estimateGas(transaction, block_identifier=None)
 
     Call a contract function, executing the transaction locally using the
     ``eth_call`` API.  This will not create a new public transaction.
@@ -845,6 +845,11 @@ Methods
         >>> my_contract.functions.multiply7(3).estimateGas()
         42650
 
+    .. note::
+        The parameter ``block_identifier`` is not enabled in geth nodes,
+        hence passing a value of ``block_identifier`` when connected to a geth
+        nodes would result in an error like:  ``ValueError: {'code': -32602, 'message': 'too many arguments, want at most 1'}``
+
 .. py:method:: ContractFunction.buildTransaction(transaction)
 
     Builds a transaction dictionary based on the contract function call specified.

newsfragments/1639.feature.rst

@@ -0,0 +1 @@
+Accept a block identifier in the ``Contract.estimateGas`` method. Includes a related upgrade of eth-tester to v0.5.0-beta.1.

setup.py

@@ -7,7 +7,7 @@
 
 extras_require = {
     'tester': [
-        "eth-tester[py-evm]==v0.4.0-beta.2",
+        "eth-tester[py-evm]==v0.5.0-beta.1",
         "py-geth>=2.2.0,<3",
     ],
     'linter': [

tests/core/contracts/test_contract_estimateGas.py

@@ -137,3 +137,30 @@ def test_estimateGas_sending_ether_to_nonpayable_function(
         estimateGas(contract=payable_tester_contract,
                     contract_function='doNoValueCall',
                     tx_params={'value': 1})
+
+
+def test_estimateGas_accepts_latest_block(web3, math_contract, transact):
+    gas_estimate = math_contract.functions.counter().estimateGas(block_identifier='latest')
+
+    txn_hash = transact(
+        contract=math_contract,
+        contract_function='increment')
+
+    txn_receipt = web3.eth.waitForTransactionReceipt(txn_hash)
+    gas_used = txn_receipt.get('gasUsed')
+
+    assert abs(gas_estimate - gas_used) < 21000
+
+
+def test_estimateGas_block_identifier_unique_estimates(web3, math_contract, transact):
+    txn_hash = transact(contract=math_contract, contract_function="increment")
+    web3.eth.waitForTransactionReceipt(txn_hash)
+
+    latest_gas_estimate = math_contract.functions.counter().estimateGas(
+        block_identifier="latest"
+    )
+    earliest_gas_estimate = math_contract.functions.counter().estimateGas(
+        block_identifier="earliest"
+    )
+
+    assert latest_gas_estimate != earliest_gas_estimate

tests/integration/test_ethereum_tester.py

@@ -283,7 +283,6 @@ def test_eth_call_old_contract_state(self, eth_tester, web3, math_contract, unlo
     def test_eth_getStorageAt(self, web3, emitter_contract_address):
         super().test_eth_getStorageAt(web3, emitter_contract_address)
 
-    @pytest.mark.xfail(reason='Block identifier has not been implemented in eth-tester')
     def test_eth_estimateGas_with_block(self,
                                         web3,
                                         unlocked_account_dual_type):

web3/contract.py

@@ -996,7 +996,9 @@ def transact(self, transaction: TxParams=None) -> HexBytes:
             **self.kwargs
         )
 
-    def estimateGas(self, transaction: TxParams=None) -> int:
+    def estimateGas(
+        self, transaction: TxParams=None, block_identifier: BlockIdentifier=None
+    ) -> int:
         if transaction is None:
             estimate_gas_transaction: TxParams = {}
         else:
@@ -1031,6 +1033,7 @@ def estimateGas(self, transaction: TxParams=None) -> int:
             estimate_gas_transaction,
             self.contract_abi,
             self.abi,
+            block_identifier,
             *self.args,
             **self.kwargs
         )
@@ -1588,6 +1591,7 @@ def estimate_gas_for_function(
         transaction: TxParams=None,
         contract_abi: ABI=None,
         fn_abi: ABIFunction=None,
+        block_identifier: BlockIdentifier=None,
         *args: Any,
         **kwargs: Any) -> int:
     """Estimates gas cost a function call would take.
@@ -1606,8 +1610,7 @@ def estimate_gas_for_function(
         fn_kwargs=kwargs,
     )
 
-    gas_estimate = web3.eth.estimateGas(estimate_transaction)
-    return gas_estimate
+    return web3.eth.estimateGas(estimate_transaction, block_identifier)
 
 
 def build_transaction_for_function(